Chapter 6: Pre-Invasion Operations
In a general sense all Anglo-American air operations conducted over the continent since the beginning of hostilities had served to prepare the way for the long-awaited invasion of northern France. Especially was this true of the great strategic bombing effort which by the spring of 1944 in its major achievement had eliminated the German Air Force as an offensive power. But there remained a multitude of tasks to be accomplished by the Allied air forces, both strategic and tactical, in immediate preparation for the war’s greatest amphibious operation.
The primary mission set forth in the over-all air plan for OVERLORD, issued on 23 April 1944, was the attainment and maintenance of an air situation in which the German Air Force would be incapable of interfering with the Allied landings. The plan in typical air force fashion called for a three-phase program. In the first or preliminary phase, extending from D minus 50 to D minus 30, the stress would be placed on counter-air force operations and on reconnaissance. Air priorities for a second or preparatory phase, running from D minus 30 to D minus 1, were named in the order of (1) the German Air Force, (2) strategic railway centers, (3) selected coastal batteries, and (4) airfields within a radius of 130 miles of Caen.1 The assault phase would begin on the night before D-day when American paratroops, in numbers not yet determined, would drop on the Cotentin Peninsula and British paratroops descend on chosen points between the rivers Orne and Dives. Over the beaches five Spitfire squadrons would fly low cover while five P-47 squadrons provided high cover. To protect the armada in the main shipping lane, five squadrons of easily identifiable P-38’s would be continuously available, flying in relays. In all, fifty-four squadrons of fighters were assigned to beach cover, fifteen to shipping
cover, thirty-six to direct support of ground forces, thirty-three to escort and offensive air fighting, and thirty-three to a reserve striking force a total of 171 squadrons.2
In a postassault phase, air would continue its destruction of the Luftwaffe and maintain bombing pressure on Germany. Other chief tasks would be to delay enemy reinforcements moving toward the invasion area, to provide air transport, to support ground forces, and to perform reconnaissance. It was anticipated that with the development of air facilities on the continent* it should be possible by D plus 40 to base as many as 116 fighter squadrons in France.3
These plans rested upon the assumption that the Allies would enjoy the advantage of overwhelming strength in the air. Estimates in April indicated that the combined forces of the AAF and RAF in the United Kingdom ready for operations as of D-day would equal 1,407 U.S. heavy bombers, 1,180 British heavy bombers, 835 light and medium bombers, 565 fighter-bombers, 2, 250 day fighters, 170 night fighters, 175 tactical and 150 photographic reconnaissance aircraft, 1,000 troop carriers, and 120 transports; opposing this vast assemblage of aircraft the Germans might dispose of 1,950 planes of all types, of which number perhaps no more than 855 could be thrown into the battle for Normandy.4 Actually, these figures proved to be underestimates. By D-day British and American air strength amounted to 3,467 heavy bombers, 1,645 medium, light, and torpedo bombers, 5,409 fighters, and 2,316 transport and troop carrier aircraft-all in combat squadrons.5 Records now available also indicate that the Germans had as many as 3,222 fighters and bombers in condition for combat on the eve of the invasion,6 but these revised figures call for no correction of the basic assumption that the invading forces would have an overwhelming advantage in the air.
The nerve center for control of the great air armadas scheduled to serve as the vanguard of the Allied assault was located at Uxbridge, where the RAF had directed its defense of London during the Battle of Britain and where the RAF’s Second Tactical Air Force had taken up its headquarters under Air Marshal Coningham. The Ninth Air Force had established an advanced headquarters there in February and shared with the Second Tactical Air Force a combined operations room from which both forces directed their operations in close consultation one with the other. Leigh-Mallory having won out in his insistence
* See above, pp. 131-32.
upon the establishment of an advanced operational headquarters for AEAF,* that too was located at Uxbridge with Coningham in command. Its authority, however, tended to be more nominal than real, for Coningham and Brereton worked in constant association to achieve an effective collaboration in the execution of directives which came down from Leigh-Mallory but had their origins in conferences of the tactical air commanders with Tedder, Spaatz, and Harris. Quesada’s IX Fighter Command shared with the RAF’s 11 Group a combined control center at Uxbridge for the direction of fighter operations, and a combined reconnaissance center supervised another vital phase of air activity. Advanced AEAF dealt directly with Montgomery, whose 21 Army Group established at Uxbridge an element to relay ground force requests and to provide such information as might be helpful in the development of an effective air-ground collaboration. Leigh-Mallory himself remained at Stanmore to supervise all AEAF operations and to coordinate the tactical support to be provided by the heavy bombers.7
A fantastically complicated system of communications and signals joined Uxbridge to its operating units and to associated forces on land and sea. The over-all air plan provided for ship-to-shore, point-to-point, and ground-to-air signals and the derivative plans of lower headquarters in their communications annexes underscored as perhaps nothing else could the fact that this was a war heavily dependent upon “magic,” to use Mr. Churchill’s term. On each of the five headquarters ships scheduled to accompany the initial landing force an air representative would be available to advise assault commanders and to direct Allied aircraft to targets in the Channel or on the beaches. In the shipping lanes three fighter-direction tenders would guide the fighters to their targets and provide necessary radar and signal controls. As quickly as possible, ground-control interception stations would go into operation on the continent. Air, ground, and naval headquarters exchanged liaison officers to assure close contact and understanding. Air support parties would accompany the assault forces to facilitate timely air assistance. Until the Allied forces could be firmly established on the continent the diverse lines of communication would be tied together chiefly through the combined control center at Uxbridge.8 This plan in its essential details was that followed.
* See above, p. 110.
The Assignments
The heaviest and most critical responsibilities assigned to any single air organization fell upon the Ninth Air Force, whose tactical air plan for the invasion, dated 26 April, expanded appropriate sections of AEAF’s over-all air plan. IX Bomber Command would devote the preliminary phase to training and to attacking railway centers, robot-bomb installations, airfields, and coastal batteries. These tasks would continue during the preparatory phase, together with the additional objective of neutralizing airfields within 130 miles of Caen and selected radar stations. Before H-hour on D-day its eleven groups of A-20’s and B-26’s would attack six heavy gun batteries which were in a position to fire on the assault forces in the Channel, those at Barfleur, Maisy, Pointe du Hoc, Bénérville, and Ouistreham I and II, and, five minutes before touchdown, the mediums would bomb seven defended localities behind UTAH beach. Those operations completed, IX Bomber Command’s bombers would return to base to be made ready for any other missions that might be assigned.9
IX Fighter Command, functioning through IX Tactical Air Command until the U.S. Third Army was ready to operate in France,* would provide escort for bombers, perform reconnaissance, and carry out offensive sweeps over France. It was scheduled to provide during the assault phase the five P-47 groups for high cover over the beach area and two P-38 groups which, with four groups of Eighth Air Force Lightnings, would maintain continuous daylight patrol over the invasion armada. Two other P-38 groups and four P-47 groups of IX TAC would bomb enemy gun batteries about H-hour and furnish direct support for the ground forces thereafter as requested. Five fighter groups would be held in readiness as part of the reserve striking force.10 The preinvasion operations interfered seriously with plans for training in conjunction with the ground forces, and it was only after a period of intensive combat that air-ground coordination reached the remarkable degree of effectiveness which became so deservedly renowned.11
The enormous responsibilities imposed on IX Air Force Service Command have already been indicated, as also those falling to IX Engineer
* On the IX and XIX Tactical Air Commands, see above, pp. 112-13.
Command.* The administrative plan of the Ninth Air Force listed additional details that had to be anticipated as comprehensively as circumstances would allow. All kinds of measures were necessary to mark supplies and equipment with the familiar Ace of Spades insignia of the Ninth, to waterproof property, and generally to comply with that well-titled manual, Preparation for Overseas Movement: Short Sea Voyage. There were problems of estimated casualties, resupply, replacement of personnel, emergency reserves, baggage, currency, and many others to be attended to. Probably the most time-consuming and exacting task which confronted the Ninth Air Force planners was the preparation of troop lists.12 When completed, the aggregate Ninth Air Force plan for the invasion weighed, as General Brereton noted in his diary, ten pounds and three ounces, and it contained 847,000 words on both sides of 1,376 pages of legal-size paper.13 After the war Brereton judged that the tactical air plans for the invasion could not have been significantly improved.14
With the controversies regarding the transportation plan and the command system out of the way, the top SHAEF and strategic air commanders developed a detailed program, which was included in the main in the over-all air plan, for the employment of Eighth Air Force and RAF Bomber Command heavies. The first master SHAEF directive after Eisenhower assumed direction of the heavy bombers on 14 April† called upon USSTAF to continue its campaign to destroy the German Air Force as first priority and as second priority to attack the enemy’s rail centers. RAF Bomber Command was to proceed with its general disorganization of German industry and to begin its share, which eventually proved to be the largest of all, of the transportation plan,15 the term usually used to indicate the Allied scheme for disrupting enemy communications. Soon afterward the Fifteenth Air Force received a directive to bomb marshalling yards in southern Germany and France in conjunction with the pre-OVERLORD attacks.16 As the time for the invasion approached, other directives, some of which were based on requests by tactical air, naval, and ground commanders, were given the strategic air forces.17 In addition to the destruction of enemy transportation, heavy bombers were to attack coastal batteries, V-bomb sites, airdromes, and bridges and to continue their deep penetrations of Germany proper in order to pin down the enemy’s fighter strength.
* See above, pp. 130-34.
† See above, p. 81.
With the main campaigns completed by 1 June 1944, the Eighth Air Force was to send 60 percent of its bombers into the Reich on D minus 3 or D minus 2 as weather permitted and to dispatch the remaining 40 per cent to plaster the Pas-de-Calais area as part of the deception plan. On D minus 1, half of its forces would rest while 25 per cent bombed seven targets in Normandy and the other 25 per cent attacked seven objectives in the Pas-de-Calais. If by that time the Allies knew the Germans had found out where the invasion blow was to land, then the total attacking force would concentrate on Normandy. (When on 4 June, D-day was postponed from 5 June until 6 June, this program for D minus 1 bombings was carried out a second time.) On D-day itself all available British and American heavies were to conduct a massive bombardment of the coast before the landings.18
This last commitment was indeed a spectacular one. The RAF would drench the invasion beaches with about 6,000 tons of bombs in the early hours of D-day. In the last half-hour before the actual landing it would be desirable, General Montgomery’s headquarters estimated, to place 7,800 tons of explosives on the shore. Of this amount only 2,500 tons could be delivered by naval guns and 500 tons by medium bombers. Thus it fell to the day-flying heavies of the Eighth Air Force to attack with 4,800 tons, and this duty made it necessary to plan on using the record number of 1,200 heavy bombers.19 In order to allow enough time for such a vast air fleet to assemble in daylight and to bomb for the full thirty minutes before touchdown, H-hour on some of the beaches had to be postponed for ten minutes, although the Eighth had requested a half-hour delay.20 And because of the congested condition of the airways on D-day, it was decided to allot OMAHA and the three British beaches (JUNO, SWORD, and GOLD) to the Eighth Air Force and leave UTAH to the Ninth. Even so, the problem of routing the thousands of aircraft that would be aloft on D-day was enormously complicated. Each of the three bombardment divisions of the Eighth would have to assemble in a special sky sector over central England, in some cases 100 miles from bases, and fly southward through definite corridors across the Channel. The bombers would approach the beaches at right angles, straight from the sea, deluge them with bombs, and withdraw by way of the Cotentin Peninsula into western England.21
Much skepticism prevailed in advance as to the value of this last-minute bombardment, and contrary to a common belief it was the airmen
who held the most conservative views. Ground force commanders tended to overestimate the effect of bomb tonnage on casemated enemy batteries, strongpoints, and the entire hideous apparatus of beach obstacles. Air force leaders were inclined to minimize the importance of driving away the crews who manned those defenses, but they agreed to lay on the attack demanded by the other services.22 Among the misgivings on the part of the air commanders was the possibility that the beaches might be so cratered the enemy could better defend them. An experiment conducted by the Eighth Air Force indicated this would be the case if the usual 500 and 1,000-pound bombs were used.23 Consequently, it was decided to attack with 100-pound demolition and fragmentation bombs except for strongpoints and areas where craters would not impede the Allied ground forces. Further concern arose over the danger that even a small degree of inaccuracy in bombing would result in the killing of large numbers of friendly troops in landing craft offshore. Spaatz, Tedder, and Leigh-Mallory accordingly recommended that the invading forces maintain a safety distance of at least 1,500 yards for the duration of the bombardment.24 Ground and naval commanders were not willing to risk losing the tactical benefits of a stunning beach bombardment, but a demonstration soon convinced General Eisenhower of the peril, and the final plan prescribed that the bombings cease five minutes before touchdown if visual conditions prevailed and ten minutes if the skies were overcast, thus allowing a safety zone of about 1,000 yards.25
After the beach bombings were over, Eighth Air Force heavies would return to base for refueling and reloading. Leigh-Mallory, who was to control the tactical operations of the strategic air forces after 1 June 1944, instructed the Eighth Air Force to carry out three other missions during D-day against bridges and such towns as Carentan, La Pernelle, Bénérville, Houlgate, Villerville, and Caen.26 His purpose was to block transportation chokepoints and thus create obstructions to German military movements,27 but widespread damage and heavy civilian casualties were likely to be attendant consequences. Both Spaatz and Doolittle regarded such bombing as not only inhumane but as likely to be ineffective except for a temporary interruption of German reinforcement. Indeed, Spaatz declared that the plan for heavy bomber employment on D-day was too inflexible, for it absorbed the entire available effort without allowing for changing battle conditions. He also criticized Leigh-Mallory’s plan to retain a large fighter reserve.28
At the commanders’ meeting on 3 June 1944 Leigh-Mallory stoutly defended his ideas and threatened that he could not accept his responsibility as air commander in chief if the plans were altered.29 He won his point and the missions were permitted to stand, although SHAEF made a partial concession to Spaatz and Doolittle by giving permission to warn all French towns near the coast by means of leaflets about impending bombings.30
The prime function of VIII Fighter Command was to provide escort for the heavy bombers, but during the months before D-day its fighter pilots devoted much effort to low-level strafing, dive bombing, and other types of operations which were useful in preparing them for assisting the ground forces.31 The general scheme for OVERLORD involved employing these fighters mainly outside the immediate assault area, which was the province of AEAF.32 The four P-38 groups flying high cover with Ninth Air Force fighters over the invasion armada would be controlled from Uxbridge, but the remaining fighter groups of VIII Fighter Command would operate under Eighth Air Force direction to protect RAF bombers and IX Troop Carrier Command transports withdrawing from France on D-day, to fly escort for Eighth and Ninth Air Force bomber missions all during the day, and to attack tactical targets in the critical area of France bounded by the Seine, the Loire, and a line running from Paris to Orléans. This last type of operation, divided into phases FULL HOUSE, STUD, and ROYAL FLUSH, would be directed a t trains, dumps, troops, airfields, and targets of opportunity past the immediate invasion area.33
By the last of May final preparations for the employment of the U.S. 101st and 82nd Airborne Divisions and IX Troop Carrier Command in the Cotentin Peninsula had been completed. The British airborne and Glider landings in the vicinity of Caen had stood as firm commitments since January, but instructions for the American units were delayed because of uncertainties regarding the arrival of a sufficient number of trained forces and Leigh-Mallory’s conviction that the Cotentin landing would probably result in an unacceptable number of casualties. SHAEF received disturbing reports of German reinforcement of the Cotentin area late in May,34 and it was apparent that the landing was likely to be perilous. The tentative plan was to dispatch pathfinder aircraft very early on the morning of the landings to drop parties who would mark the landing zones with lighted tees and establish radar beacons to guide the main forces. The air trains of unarmed transports
would fly across the Channel at 1,000 feet, skirt the bristling Channel Islands, and cut across the well-defended Cotentin Peninsula from the west. It could be anticipated that drop and landing zones might be difficult to locate, and that antiaircraft defenses would be alerted. Small-arms fire could shoot up the low-flying troop carriers, which did not have leak-proof tanks, and the Allies knew the Germans had stakes, spikes, artificially flooded areas, and other traps to catch the descending paratroops and gliders.35 furthermore, there was little in the way of air protection which could be given the vulnerable airborne forces except a few Mosquito night fighters. RAF Bomber Command planned to bomb the area just before the airborne attack in the hope of inducing the enemy to expose his searchlights and flak to strafing by night fighters; and a diversionary force of RAF Stirling bombers would drop Window to simulate a troop carrier operation going to a different area, where it would discharge dummy paratroops and noisemakers.36 Still, the American operation was clearly hazardous and might even prove disastrous. Leigh-Mallory regarded it as a potential holocaust and dutifully informed the supreme commander on 29 May of his views.37
General Eisenhower made the lonely decision that the U.S. airborne landing was feasible and in any event vital to the seizure of UTAH beach, which in turn was vital for the conquest of the port of Cherbourg.38 Then, on 31 May 1944, the final airborne plan was issued. At 0200 on D-day 432 aircraft of IX Troop Carrier Command would begin dropping the 101st Airborne Division in the general area about Ste.-Mère-Église, followed at 0400 by transports pulling 50 gliders. The 82nd Airborne Division which not long before had been scheduled to land on the next night was instead placed in the initial assault. From 369 aircraft and 52 gliders its parachute and glider infantry would land, beginning at 0121, to the west of the 101st Airborne Division sector. The two divisions were to gather up their guns, jeeps, and other equipment and attempt to organize in time to obstruct German movement toward UTAH beach. On the evening of D-day reinforcements of men and equipment would be flown in.39
What if the weather were bad on D-day, bad enough to prevent visual bombing or even flying? That such might be the case was one of the factors General Eisenhower had considered when he recommended the postponement of the invasion from May to June. Predictions for the first few days of June confirmed the worst fears; and if 7 June were allowed to go by, OVERLORD could not jump off for another
month because of the tides. On 1 June, AEAF headquarters prepared a bad-weather plan for air operations. If visual conditions did not prevail on D-day (and they did not), the Eighth Air Force would have to use H2S-equipped pathfinder aircraft to lead the bomber forces to the invasion beaches and the town of Caen, both of which would be bombed blindly. Also, the bombardiers would have to delay releases for a few seconds to make sure the bombs did not fall on the invasion forces.40 Recent experiences in radar blind bombing had indicated that little accuracy could be expected, although the Eighth Air Force had made notable efforts during the spring of 1944 to train key crews in the use of H2S. General Doolittle took the additional precaution of planning to break his heavy bomber forces into 200 six-aircraft formations instead of 40 thirty-bomber boxes and to fuze all bombs for instantaneous detonation so as to avoid unnecessary cratering of the beaches. The medium bombers of the Ninth Air Force were to employ OBOE in the event of adverse weather and attack only the principal targets on the list. Probably they would not even attempt to bomb the other objectives.41
There remained even the nightmarish possibility that because of weather conditions no bombers could take to the skies on D-day. General Montgomery said the invasion would not be scrubbed in that event. Accordingly, the air commanders planned to hold their bombers in readiness at base to await a break in conditions and to dispatch half the fighter-bombers available to attack the invasion beaches at H minus 15 minutes. This fighter-bomber operation seemed likely to prove suicidal for most of the pilots involved. But the invasion machinery had to be set in motion forty-eight hours before H-hour.42 Spaatz, Doolittle, and Kepner privately vowed to protect the doughboys with all the forces they could get into the air, even if they themselves were lost in the process.43
The formal presentation of all OVERLORD plans took place on 15 May 1944 at the final full-dress conference held at SHAEF. After that, the various commanders, headquarters, and combat units busied themselves making preparations, checking details, and generally attending to last-minute matters. Doolittle was worried about a possible enemy effort to neutralize English airfields by means of parachutists at the critical period and suggested that defenses be tightened.44 Urgent messages were sent to Washington to expedite the shipment of small bombs and high-octane gasoline. Washington, in turn, prepared to rush enormous
reinforcements of aircraft and crews to Britain if they were needed.45 Spaatz drafted his recommendation for the eventuality that Hitler might use poison gas to combat the invasion: the Allies should not retaliate in kind on German cities but continue to use the most harmful weapon they possessed, the heavy bomber.46 The Mediterranean Allied Air Forces had orders to reinforce or assist the northern invasion forces should it prove necessary, and the first shuttle-bombing mission between Italy and the Soviet Union was carried out just before D-day to distract the Germans on the eve of the assault on Normandy.
Preparations reached all the way into the smaller air units, touching such personal matters as mail, leaves and furloughs, rotation, freedom of movement, and rest periods just before D-day. Morale was undoubtedly high, conspicuously so,47 and tension was great. To be sure, invading continental Europe was nothing new to thousands of airmen who had been engaging in the practice for many months. But the historic importance of the events about to unfold was everywhere sensed. As for OVERLORD planning, it continued until that operation, overwhelmingly successful, merged into other strategic phases of the European war. Only the preassault stage of preparations was completed when General Eisenhower decided at 0415 on 5 June 1944 to launch the invasion despite disturbing weather reports, or when General Doolittle gave orders at 2200 that night to prepare the Eighth Air Force’s heavies for blind bombing of the beaches, or when at midnight Eisenhower and Brereton watched IX Troop Carrier Command transports take off with blackened paratroops for the Cotentin Peninsula.48
During the last few weeks before D-day the leaders and planners, from such august headquarters as SHAEF, USSTAF, AEAF, and RAF Bomber Command down to the airplane commanders and crew chiefs, had labored intensely to perfect air preparations for OVERLORD. An unprecedented degree of harmony in purpose, if not always in methods, had prevailed, and the spirit of cooperation among the various headquarters and individuals would later seem one of the more remarkable features of a long war. From the first General Eisenhower had set the pace for mutual trust, friendliness, and determination, and his example was an inspiration. He made a brief statement at the air commanders’ meeting on 31 May 1944, where the minutes record:
The Supreme Commander said that he would like to take this opportunity of saying a few words to the Commanders and their Staffs. He said that
for him, military operations were always a matter of human beings and not of mathematical calculations, and that he would like it to be known by the men who were fighting the battle how much the Commanders reckoned on what they had done and would do. In the preliminary stages of planning a good motto was “Doubts must come up, only enthusiasm must go down.” Now that the plans were completed and the battle on, doubts in the minds of the Commanders must not be allowed to reach those who were fighting the operation, and he instanced the airborne operation as one that had been criticized. They must feel that the best plans had been made and that the operation was worthwhile. He said he would like a message from the Air Commander-in-Chief, and one from himself, to be passed to crews at final briefing.49
Attrition of Enemy’s Railway System
Until 10 March 1944 the Ninth Air Force had been primarily engaged in assisting the strategic air forces, to the restlessness of both Leigh-Mallory and Brereton, but on that date its bombers were freed for concentration on preinvasion operations.50 The Eighth Air Force still had first call on the Ninth’s fighters for escort tasks, a prerogative which it used more liberally than tactical air commanders liked.51 By 1 April, however, the demands of the invasion became paramount in the apportionment of all air effort. USSTAF continued to have as its first priority the over-all reduction of German air strength and RAF Bomber Command carried on its program of attacks on industrial centers,52 but the heavies, which until 1 June took their assignments from Tedder, found other targets requiring an increasing proportion of their effort. As the weeks went by, the transportation campaign absorbed more and more of the effort, and at times the heavy bombers gave high, even first, priority to attacks on robot-bomb launching sites in France. Priorities for other target systems airfields in France, oil production, coastal defenses, and ordnance depots shifted repeatedly.53 The smaller forces of the AEAF* took their orders from Leigh-Mallory, who elected to spread his commitments so that five or six different bombing campaigns would be going on simultaneously, although his new deputy in AEAF, Maj. Gen. Hoyt S. Vandenberg, advised concentration on one program after another.54 Each tactical air force worked within a flexible framework permitting adjustment to conditions of weather, problems of training, and other considerations, but the transportation campaign in general held first claim.
The cardinal purpose of the transportation plan approved by Eisenhower
* As of 1 April, AEAF included 496 American and 70 British medium bombers, 96 American and 38 British light bombers, and 670 American and 1,764 British fighters.
on 26 March, after a protracted controversy,* was to isolate the invasion area. As Leigh-Mallory’s railway experts envisaged the task, the isolation was to be achieved mainly through extensive bombing of vital rail centers and repair facilities. Already the French system, the Société Nationale de Chemins de Fer Français, or SNCF, was believed to be in a bad way. Aside from the wear and tear it had suffered during several years of wartime use, the SNCF had lost perhaps one-third of its locomotives through expropriation by the Nazis. Deficiencies of track, rolling stock, reliable workmen, coal, and other prerequisites had brought French rail transportation to a condition of severe strain. If two-thirds of SNCF capacity were devoted to carrying German military traffic, as AEAF experts contended, about 45,000 tons of well-placed bombs should produce a chaotic situation for the enemy.55 The Belgian system was believed to be almost as vulnerable as the French, and a railway attrition campaign in the Balkans carried on by the Mediterranean Allied Air Forces could be expected to aggravate Germany’s transportation crisis. When the enemy’s railway system had lost its flexibility and much of its capacity from such operations, the Allies would lay on an interdiction program shortly before D-day to seal off Normandy.
The transportation plan singled out as the chief targets routine servicing facilities in the key rail centers, since their destruction would be likely to cripple the entire system immediately.56 Damage to locomotives, marshalling yards, switches, rolling stock, tracks, and stations would be regarded as a bonus, an incidental contribution to the ruin of the enemy’s railway systems. It was planned to concentrate bombing attacks on rail centers in Belgium and the Région Nord of the SNCF, where the network was thickest. A rail chaos there would prevent the Germans from reinforcing their counterinvasion divisions at the critical time from the area where most of their reserves were stationed. Also, coal for locomotives might be cut off from the rest of France, and confusion would be created with respect to the site of the invasion. As it was supposed to work out, the Normandy area, far to the southwest, would be isolated while the Germans would be led to believe the Allies were endeavoring to interdict Calais.
When the Ninth Air Force became available for preinvasion bombing on 10 March 1944, it was assigned thirty targets in Belgium and north central France from the list of the transportation plan, although
* See above, pp. 72-79.
the plan itself was still under debate and only nine of the targets had been cleared at that time for bombing because of the hesitations of the British War Cabinet about exposing friendly civilians. During March the Ninth went ahead with such missions as were possible for it, attacking four times the rail center at Creil, which was destined to become the most bombed target of this type in France. Brereton’s air force also achieved substantial success in bombing the rail centers at Hirson, Amiens, and Charleroi.57 The Second TAF participated in the transportation campaign by attacking other rail centers in northwestern France and Belgium, and RAF Bomber Command, which was experimenting in methods of attacking railway installations at night without slaughtering the inhabitants in their vicinity, inflicted considerable damage on Le Mans, Amiens, Laon, Aulnoye, Trappes, and Courtrai.58 By the end of March no spectacular results were apparent in the rail center campaign, but champions of the transportation plan drew encouragement from the havoc wrought on repair installations and marshalling yards and had won, moreover, Eisenhower’s acceptance of the plan.
In the first half of April the Ninth Air Force continued to operate with usually good results against the rail centers. Among the chief attacks was an afternoon mission on 8 April to Hasselt, in northeastern Belgium, by 163 B-26’s, which dropped 263 tons of bombs, and by 101 P-47’s which discharged 120 x 250-pound bombs in diving attacks.59 Two days later smoke was still rising from the damaged repair shops when 56 P-51’s returned to dive-bomb the target. On 9 April a spirited fighter operation, involving 48 P-47’s, stopped troop and freight trains moving toward the invasion area and brought damage to rail yards in several towns. Namur and Charleroi, two of the major Belgian targets, received punishment from the Ninth Air Force on 10 April when 148 Marauders dropped 184 tons on the former and 40 Marauders and RAF Mitchells attacked the latter. On the following day 193 Marauders went back to Charleroi and discharged 347 x 1,000-pound bombs and 1,106 x 250-pound bombs in the general area of the rail center with results ranging from poor to good. By this time the Ninth Air Force had worked out very satisfactory methods for attacks such as these. Usually, four or five groups of B-26’s with about thirty-seven aircraft per group would bomb a single rail center. Instead of having massive formations drop on signal from a lead airplane, Brereton ordered that the attacking force break up into numerous four or six-plane sections,
a measure which sharply improved accuracy and consequently reduced the danger to civilians. Furthermore, the Thunderbolts, which ordinarily accompanied the heavy bombers, performed so successfully in strafing and dive-bombing rail targets that Leigh-Mallory directed the use of as many RAF Spitfires as possible for escort in order to release AAF fighters for the transportation attacks.60
By the middle of April the Second TAF was regularly sending out Typhoons and Mosquitoes to bomb and shoot up transportation targets near the coast, and Bomber Command heavies were proving that expertly led night formations bombing from low altitudes could approximate the operations of daylight attackers in effectiveness.61 Scrutinizing the estimates of casualties and concluding they were not too large, Churchill lifted the ban on most of the occupied cities toward the end of April except for such heavily populated areas as Paris, Le Bourget, Nancy, and a few others, which action left Tedder free to assign most of the rail center targets to the air forces.62 To the Eighth Air Force went twenty-three targets in Belgium, northeastern France, and western Germany. The Fifteenth Air Force received twenty-two targets in southern France and central Germany, RAF Bomber Command’s commitment comprised twenty-seven targets (later thirty-nine) in northwestern France, the Paris area, and Belgium. Targets assigned to the AEAF numbered about thirty (finally eighteen), scattered about in Belgium and northern France. The system for classifying damage was to be: A, when nothing more was needed than occasional dive bombing to keep the rail center in disrepair; B, where damage was great enough to allow suspension of all but precision attacks; and C, for rail centers which were only slightly affected and where all kinds of attacks were permissible.63
The Ninth Air Force achieved excellent results on 19 April when 182 B-26’s and more than 50 fighters attacked Malines, Namur, and Hasselt. On 20 April, P-47’s dive-bombed Mantes, west of Paris, and Creil. Fighters of the Ninth, which now included considerable numbers of Mustangs as well as Thunderbolts, prosecuted the campaign with conspicuous success on the following three days, attacking Namur, Haine-St. Pierre, Hasselt, Montignies-sur-Sambre, Malines, and St. Ghislain. In all, twenty-two targets received fighter-bomber visitations in the last two weeks of April.64 Perhaps the most spectacular operation occurred on 23 April, after Eighth Air Force fighter pilots returning from escort missions over the Reich reported an abnormally
large concentration of rolling stock at Namur. More than 100 Ninth Air Force Mustangs and Thunderbolts hurried to the city and inflicted serious damage on the railway installations. And there were other fighter-bomber successes against Louvain, Mantes, Monceau-sur-Sambre, and various other targets, most of which had been attacked earlier by bombers. The B-26’s of the Ninth were also active, although bad weather kept them from operating on several days. On 27 April, 100 Marauders dropped about 400 bombs, most of them of the 1,000-pound size, on Cambrai, and on 30 April, 143 mediums attacked Bethune and Somain. The A-20 light bomber entered the Ninth’s campaign on 27 April, when 71 of them bombed Arras; on the 30th, the same number attacked Busigny. Eighth Air Force heavies conducted their first missions under the transportation program on 27 April, dropping 342 tons on Blainville and 230 tons on Châlons-sur-Marne, with good results in both cases.65 As for the RAF, its Second TAF was out almost every day attacking marshalling yards near the Channel, and Bomber Command was piling up a notable series of victories in wiping out rail centers during heavy night attacks.
By the end of April it was evident that enormous damage was being done. Some 33,000 tons had fallen on the rail centers, and at least twelve important targets were already in Category A.66 The Germans, whose antiaircraft defenses had been very weak, were beginning to concentrate more guns around the rail centers; as yet they had not contested the Allied operations with their fighters. The enemy was also displaying much resourcefulness in repairing the bombed centers, in some cases getting through-traffic re-established within a few hours after the bombings. It was becoming obvious that the Allies would have to reattack frequently, far more than they had counted on, and that their operations would have to be planned in a most scientific manner if the rail centers were to be kept out of use. Moreover, it was very difficult to assess the real effectiveness of the bombings. With a wealth of intelligence data coming in from occupied Europe and by means of photographic reconnaissance, the Allies might gauge the train count of certain centers and learn the approximate number of locomotives and cars destroyed, the extent of structural damage to facilities, and the length of time it took the Germans to repair main lines. But was physical damage a sound criterion for judging enemy military movements? From evidence at hand by the last of April it seemed that only French and Belgian traffic was being knocked off the rails.67 The Germans
were still moving their troop and supply trains, which naturally enjoyed priority, without serious delay. But it was well understood that the transportation plan was a long-term program, and less than half the pre-D-day tonnage of bombs had been dropped. Leigh-Mallory issued a paper on 30 April urging the air forces to step up their prosecution of the campaign and calling in particular upon the Eighth Air Force to begin its full participation.68
During May 1944, the month of the heaviest preinvasion bombing, transportation attacks were greatly intensified by all air forces and cunningly focused on routes which led into Normandy while seemingly concentrated on those serving other areas. On 1 May, eleven different B-26 forces of the Ninth attacked Mantes, Montignies-sur-Sambre, Douai, Monceaux, and Valenciennes. Simultaneously, thirty-seven Bostons bombed Charleroi, and Thunderbolts dive-bombed Haine-St. Pierre, St. Ghislain, Amiens, Arras, and Valenciennes. On the same day the Eighth Air Force carried out its first major mission against rail centers, dispatching 328 heavy bombers and 16 groups of fighters to drop more than 1,000 tons on the Troyes, Reims, Brussels, Liége, Sarreguemines, and Metz marshalling yards. Ninth Air Force fighters went out on 2 May in ten different forces of about twenty-eight aircraft each to drop 250 and 500-pound bombs on Le Mans, Aulnoye, Tergnier, Hasselt, Mantes, Tourcoing, Charleroi, Somain, and Péronne while six light and medium bomber forces attacked Valenciennes, Busigny, and Blanc-Misseron. Several days of bad weather interrupted the program until 7 May. Between that day and the 11th the Ninth bombed Calais, Aerschot, Mons, Creil, Tournai, Mézières, Arras, Bethune, Cambrai, and smaller centers. Fighter-bombers usually carried out precision attacks after the B-26’s and A-20’s had damaged the main parts of the target areas. On 11 May, Eighth Air Force B-17’s dropped 600 tons on Saarbrücken, Luxembourg, Ehrang, Konz-Karthaus, Bettemburg, Thionville, and Völklingen while B-24’s bombed Mulhouse, Belfort, Épinal, and Chaumont with 440 tons.69 And the British air forces were equally active. Bomber Command proved so successful, in fact, that it was assigned twelve targets originally allotted to the tactical air forces.
Soon after the middle of May the pre-D-day rail center program was close to completion except for the USSTAF contribution. Occasional reattacks were of course necessary, and fighters conducted regular surveillance over the bombed centers for evidence of activity. But the Eighth and Fifteenth Air Forces still had the bulk of their tonnage to
deliver. On 23 May, six combat wings of Eighth Air Force Fortresses attacked Épinal, Metz, Saarbrücken, Bayon, Chaumont, and Étampes. Two days later fourteen combat wings dropped heavy tonnages on Mulhouse, Belfort, Tonnerre, Sarreguemines, Thionville, Metz, Blainville, Liége, Brussels, Charleroi, and Alost. On 27 May, Ludwigshafen, Mannheim, Karlsruhe, Strasbourg, Konz-Karthaus, Neunkirchen, and Saarbrücken were successfully bombed, this mission proving to be the only one in the transportation program in which the enemy’s fighters put up significant resistance to American bombers, nine of which were shot down on this occasion. On 30 May the Eighth attacked Troyes, Reims, and Brussels, and on 4 June it bombed various transportation targets in the suburbs of Paris. Of its twenty-three allotted targets, the Eighth Air Force placed fifteen in Category A and eight in B. Its operations during the last of May had been of devastating effect and brought its total for rail center bombings up to 13,000 tons.70
The Fifteenth Air Force had originally been assigned twenty-two rail centers in central Germany and southern France. The German targets were subsequently dropped as unnecessary for OVERLORD, and the Fifteenth actually devoted most of its railway bombings to targets in Italy and the Balkans. USSTAF having on 24 May 1944 issued the necessary orders, 600 of the Fifteenth’s heavy bombers from 25 to 27 May ranged over southern France almost without interference, dropping more than 3,000 tons on fourteen different targets. St.-Étienne, Nice, Lyon, Chambéry, Grenoble, Avignon, Marseille, and Nîmes were the chief objectives, and reports of damage to railway installations in those localities were highly satisfactory, five falling in Category A.71
By D-day Leigh-Mallory’s headquarters estimated that fifty-one of the eighty rail centers in the north were in Category A, of which twenty-two were credited to RAF Bomber Command, fourteen to the AEAF, and fifteen to the Eighth Air Force. By less rigid standards of measurement, the damage was far more extensive, for practically all of the targets were judged unusable for the enemy’s purposes. The total tonnage of bombs amounted to more than 71,000, 46,000 of which were dropped by Bomber Command alone. Losses to attacking aircraft had been very light, especially where the daylight bombers and the fighters were concerned. Accuracy had been high, in some cases outstandingly so.72 French and Belgian casualties had been far below the estimates of both pessimists and optimists, and the reaction of the occupied
populations to the bombings, while it gave the Allies some uncomfortable moments, was not alarming. But in the face of these achievements, by 19 May 1944 railway traffic in the west had declined by less than one-third – just to the point that transportation plan advocates had earlier predicted would begin to interfere with military transportation. Doubtless, the Germans had been hurt and their traffic would fall at an increasing rate before the Normandy landings. But SHAEF G-2 reported on 20 May that the rail center bombings were not yet producing the effects expected.73
To supplement the transportation plan, Leigh-Mallory authorized wide-scale fighter sweeps against moving trains on 20 May, when civilian passenger traffic was believed to have ceased.74 For some time fighters had been shooting up trains, to the nervousness of USSTAF headquarters, where it was feared that civilians were being killed indiscriminately.75 Now the practice would be carried on openly and on a large scale. In the next two weeks fighters damaged about 475 locomotives and cut railway lines at 150 different points. The most sensational attacks were the CHATTANOOGA CHOO-CHOO missions, the first of which took place on 21 May when 763 AEAF fighters swept over the northern half of France and 500 Eighth Air Force fighters ranged over Germany firing and bombing at trains.76 Another occurred on 25 May when three Ninth Air Force fighter groups operated over the Rhineland and northern France and more than 600 Eighth Air Force fighters shot up trains in Belgium and France. Other outstanding CHATTANOOGA missions were carried out by 571 Eighth Air Force fighters in eastern Germany and Poland on 29 May and by the Ninth Air Force in France on 2, 3, and 4 June.77 These operations furnished good practice for fighter pilots in attacking ground targets, a skill they were to develop to a high degree after the invasion, and they brought about enormous disruption to enemy traffic and ruin to equipment while producing important psychological effects on railroad personnel. French train crews deserted in large numbers, especially after fighters began to drop belly tanks on stalled trains and to set them afire by strafing. This situation caused the Germans to employ crews of their own nationality on the more hazardous runs, and after 26 May railway operations in daylight were sharply reduced even in cases where the lines were unbroken.78
Probably the decisive phase of the long transportation program was the brilliantly successful interdiction campaign against bridges. For
months before the Normandy landings much doubt prevailed in military circles that enough bridges could be destroyed in time to benefit OVERLORD. River crossings, especially those of steel construction, were difficult to hit from the air, and the enemy could be counted on to discourage precision bombing by arraying antiaircraft guns around them. Moreover, the amount of bomb tonnage necessary to finish off a bridge was thought to be high, almost prohibitive. But during the spring of 1944 General Spaatz began to urge that experimental attacks be carried out on bridges, for it was apparent that success in this matter would greatly contribute to the transportation campaign. General Brereton likewise pressed for efforts to remove bridges leading toward or into the invasion area. Substantiation for the views of these air generals came out of Italy, where operation STRANGLE showed not only that bridge-breaking was feasible but that it was the most effective way to block the enemy’s movements. General Eaker made known the successes of his air forces in sealing off part of the Italian peninsula by means of bridge destruction,* and General Anderson brought back from a visit to Italy enthusiastic accounts of the success of STRANGLE.79 Pressure for a bridge campaign grew when it was realized that an experimental attack carried out by RAF Typhoons on 21 April 1944 on several French and Belgian bridges had rendered the crossings unusable even if it had failed to destroy them.80 Soon afterward, on 3 May, Montgomery’s headquarters officially requested the air forces to take out several bridges over which the enemy might move reinforcements into Normandy, and his representative subsequently expressed to Leigh-Mallory the view that bridge destruction would be more decisive than “pin-pricking on rail communications.”81 Still there was hesitation. The British railway expert, E. D. Brant, estimated that 1,200 tons would have to be expended on each of the Seine bridges, a costly undertaking which could hardly be afforded in view of other preinvasion commitments. Leigh-Mallory suggested that Spaatz’s heavy bombers attempt the campaign. But Spaatz believed that too much bomb tonnage would be required, since the heavies would have to attack from such high altitudes, and that smaller aircraft, as experience in Italy indicated, were better suited for the task. After discussing the matter thoroughly on 6 May, Leigh-Mallory finally turned to other matters, remarking that he did not care to see a waste of effort at that time.82
* See below, pp. 373-84.
On 7 May all serious doubts were swept away by a notable Ninth Air Force operation. Eight P-47’s dropped two 1,000-pound bombs apiece on a 650-foot steel railway crossing over the Seine near Vernon and demolished it.83 This attack, which seems to have been made on Brereton’s initiative,84 was one of four executed that day by P-47’s and B-26’s. While the Vernon operation was the most clearly successful demonstration, bridges at Oissel, Orival, and Mantes-Gassicourt were badly damaged and soon put out of use.85 Leigh-Mallory, having thus been convinced that the tactical air forces could do the job,86 on 10 May directed his forces to begin the destruction of bridges over the Albert Canal and the Meuse River, an enterprise that would suggest Allied concern with the Calais region but would nevertheless help cut off Normandy. SHAEF, alarmed by a report of its G-2 that the rail center bombings were causing only “some slight delay” in enemy rail movements, soon prepared an extensive interdiction program for the air forces which called for cutting all bridges up the Seine to Mantes and up the Loire to Blois and at critical points in the so-called Paris-Orléans gap stretching between the two rivers.87 Because of the ever present and by now paramount consideration of security, the Loire bridges would have to wait until D-day. In order to achieve maximum surprise against the Seine bridges, it was decided that the air forces should withhold their attacks there until shortly before the invasion, and then lay on a series of staggering blows in rapid succession. Since routes over the Seine led into the Pas-de-Calais as well as Normandy, it was not likely that the Germans would guess from these bombings where the Allies were going to land.
Medium bombers and fighter-bombers of the Ninth Air Force conducted several good attacks on Belgian bridges between 11 and 26 May, breaking those at Herentals, Liége, and Hasselt and severely damaging others. On 24 May the ban on the Seine bridges was lifted, and on the 26th they became first priority for the AEAF.88 Accordingly, B-26’s and P-47’s began a spectacular campaign of low-level attacks, striking Le Manoir and Poissy on 26 May, Juvisy, Le Manoir, Maisons-Lafitte, and Le Mesnil Ande on 27 May, and Mantes, Orival, Rouen, and Maisons-Lafitte on 28 May. Conflans, Orival, Juvisy, and Athis caught heavy attacks on 29 May, while Mantes, Rouen, Meulan, Bennecourt, and Conflans were further damaged or broken on 30 May, along with several highway crossings.89 In these operations it became clear that the
B-26 was the choice weapon,90 although RAF and Ninth Air Force fighters were frequently employed to finish off damaged bridges and to block tunnels. The combination of B-26’s dropping 1,000-pound bombs, P-47’s diving with 500-pounders, and Typhoons firing rocket projectiles proved devastating. River crossings over the Seine were falling rapidly to Allied air power, and despite superhuman efforts German reconstruction was not keeping pace with Allied damage.
Even so, by 1 June 1944 the enemy’s transportation system had still not reached the final state of collapse desired by the Allies, although the 45,000 tons originally allotted for bombing rail centers had been greatly exceeded. The Germans were repairing their bombed marshalling yards and railroad tracks with admirable efficiency, and they were fairly successful in redistributing their traffic flow so as to avoid the worst-damaged points.91 It seemed that essential military movements were still taking place although much important work, such as the completion of the Atlantic Wall, had to cease because of transportation difficulties.92 North of the Seine was Field Marshal General Gerd von Rundstedt’s large Fifteenth Army, poised to meet an expected assault on Calais. Unless the line of interdiction became perfect, he would probably be able to shift much of his strength into Normandy after D-day. Thus, the best hope of the Allies to seal off the invasion area was to complete the destruction of all twelve railway and fourteen highway bridges over the Seine.
Last-minute attacks on the Seine bridges produced the maximum results: the impassibility of all crossings below Paris. Marauders, Thunderbolts, Lightnings, and Typhoons attacked every day and night, bombing and rebombing until every bridge was unusable. The Germans, of course, made desperate attempts to repair their shattered bridges, but strafing made it difficult and demoralizing work, and even when reconstruction was successful, the Allies would promptly bomb again. Strafing also interfered with the enemy’s efforts to unload freight from trains at the broken crossings for ferrying across the Seine to trains on the other side, and the Allies could strand the trains by cutting lines or destroying locomotives. The line of interdiction along the Seine was a fact by D-day. And the total tonnage expended in the railway bridge campaign amounted to only 4,400, averaging per bridge about one-fifth the weight originally expected. Clearly, the Ninth Air Force had carried off most of the honors for this phase of the transportation plan.93
The battle against enemy transportation was a splendid success on the eve of D-day. It “opened the door for the invasion,” as Spaatz later informed Arnold.94 British-American aircraft had dropped a total of 76,200 tons (on rail centers 71,000, bridges 4,400, and open lines 800) and would aim 78,000 tons more at transportation targets before France was free of the German. Railway traffic in France fell off dramatically between 19 May – when the Allies were somewhat discouraged about the transportation bombings and 9 June 1944, the index dropping from 69 to 38 (based on 100 for January and February 1944). By mid-July the index would be only 23, and traffic in northern France would be practically at a standstill.95 Von Rundstedt had been unable to move effective reinforcements into the Seine-Loire triangle at the time of the invasion, and his forces had been committed piecemeal and could not even be deployed as units.96 Thus the Allies had won their premier objective in the transportation campaign: they were able to build up their forces in Normandy from across the Channel faster than the Germans could reinforce theirs from adjacent areas in France.
Whether the rail center attacks subject of a long controversy among invasion planners in early 1944 had been necessary or not in accomplishing the wreckage of Germany’s transportation system continued to be a subject of some debate. Even the German commanders held varying opinions, and captured enemy records can be interpreted to support several points of view. Von Rundstedt later told interrogators that strategic bombing had little or no effect on the French railway systems until late in July 1944. The German officer who was in charge of military transport on railways in the west stressed the catastrophic effects of Allied interdiction, especially bridge-breaking.97 Other enemy evidence indicated that the attritional bombings of the railway repair centers and marshalling yards were decisive in stopping traffic. The fact remained that the Germans suffered indescribable and often ludicrous difficulties in moving their troops and supplies, whether in reinforcement or evacuation.*
Allied opinion about the different aspects of the transportation campaign remained consistent; those who had sponsored the rail center bombings in the first place generally thought they had been right, and the champions of interdiction continued to argue their side of the case. The evidence, Germany’s ruined communications, lent itself to a variety of interpretation. In November 1944, shortly before he lost his life
* See below, pp. 219-27.
on a flight to India, Leigh-Mallory presented to Eisenhower a “despatch” summarizing the AEAF’s contributions. It is not surprising that he hailed the rail center program as fully realized and claimed that his beliefs had been confirmed.98 Solly Zuckerman prepared two studies after the invasion in which statistics seemed to prove the higher importance of attrition as compared to interdiction.99 General Brereton and Air Marshal Harris, both of whom had favored the rail center campaign, looked back upon it after the war as very effective in bringing about the results they had intended. Air Marshal Tedder said the rail center bombings had been the main factor in producing the collapse of German communications, an achievement which he said had come about more rapidly and more completely than he had anticipated.100 SHAEF G-2 reversed its position of May 1944 to conclude in November that attrition had proved more effective in France before D-day than interdiction.101 And there was scattered support from other analyses to justify the rail center bombings. Perhaps most telling of all was the decision of the Allies to continue bombing rail centers, which they did until the end of the war, though not without differences over the probable effectiveness of such attacks and doubts about results.
On the other hand, SHAEF G-2 in May and June 1944 assessed the attrition campaign as a severe disappointment, if not an alarming failure.102 As late as D plus 1 the Germans seemed to possess several times the railway resources they needed, a fact which, if true, refuted the champions of attrition. Two Ninth Air Force studies of July 1944 judged the attrition program as having almost no effect in isolating Normandy, while interdiction was considered decisive.103 General Spaatz and most USSTAF officers continued to look upon the rail center bombings as much less important than bridge-breaking and line-cutting, and General Arnold seems to have agreed.104 The U.S. Embassy’s railway experts likewise remained consistent by deciding a few months after OVERLORD that interdiction had been the decisive phase of the transportation campaign. A comprehensive study of the U.S. Strategic Bombing Survey compiled under the direction of Gen. Omar N. Bradley soon after V-E Day drew a similar conclusion.105 Also, the president of the French railway system said rail center attacks were less significant than those on bridges.106 Finally, an AAF evaluation board report based largely on French railway records concluded after a laborious examination of evidence and balancing of factors: “The pre-D-day attacks against French rail centers were not necessary,
and the 70,000 tons involved could have been devoted to alternative targets.”107
Neutralization of German Air Bases
From the first, OVERLORD planners emphasized the need to neutralize airfields in western Europe from which the German Air Force might operate against the Allied invaders. The minimum objective was to drive the enemy’s fighter squadrons back to bases in the east so that they would enjoy no advantage over Allied fighters which flew out of England. But the more the Allies could widen their air supremacy over the enemy the better. The POINTBLANK campaign against German aircraft production and the GAF itself reached a successful climax early in 1944. This victory of the Allied air forces signified that the enemy would not be able to prevent the invasion by air power, as otherwise he might have. Crippled as his air force was, however, he still possessed one. By sheltering it and expending it frugally against the continuous provocation of Allied bomber fleets over the Reich, he might be able to throw an estimated 900 aircraft, including 450 bombers,* against OVERLORD at the critical time and with telling effect.108
Allied apprehension as to the use that might be made of such a force finds confirmation in German plans. In the spring of 1944 Hitler himself ordered the “Baby Blitz” on England in the hope of spoiling Allied invasion preparations.109 But the Germans did not have enough bombers to do any serious damage in these night attacks on London and the southern ports, especially in the face of good defenses and counterattacks on their bases.110 But many of the Luftwaffe’s units could be shifted to France once the invasion began – Goering later claimed that he was prepared to have this done, that his organization had even guessed right about the landing site.111 Since von Rundstedt was resigned to the fact that the Luftwaffe could not protect his communications and installations, he decided that this force would be used altogether
* If a captured file of the German high command known as Auswertung der Einsatzbereitsch der fliegenden Verb. vom 1 August 1943 bis November 1944 is correct, the average German air strength in May 1944 for all fronts stood as follows:–
|
Called for (Soll) |
In Existence (Ist) |
In a State of Readiness (Einsatzbereit) | |
| Fighters | 2,680 | 1, 729 | 1,195 |
| Night fighters | 1,052 | 644 | 434 |
| Twin-engine fighters | 385 | 318 | 153 |
|
Light bombers (Schlacht) |
937 | 869 | 639 |
|
Bombers (Kampf) |
1, 824 | 1,259 | 801 |
for offensive operations to repel the invaders.112 Fighters might be withdrawn from every front and the Reich itself in order to attack the OVERLORD forces.113 From bases deep in France German bombers could contribute their power to the counterassault along with the robot bombs that were about ready to function. German plans presupposed the availability of adequate air bases in France.
There were approximately 100 airfields within 350 miles of the Normandy shore from which the German Air Force could operate. Some of these bases were well built up as a result of several years of use by, in turn, French commercial airlines, the RAF, and the Luftwaffe. In the spring of 1944 most of the air bases were empty except for a few antishipping and reconnaissance squadrons which shifted about uneasily from one field to another depending on Allied activities. But the bases existed and could easily be used again. Thus the Allies felt it necessary to damage all of them. Yet airfield attacks were likely to be unproductive under these circumstances. The enemy could fly his airplanes away before the bombings; runways and landing areas thoroughly postholed in the morning could be filled by late afternoon; and damage to hangars, repair facilities, and gasoline dumps would not be permanently crippling in effect. American experiences in the Pacific war had demonstrated how fighters could operate from ruined airfields or even flat stretches of ground with scanty supplies of fuel, ammunition, and spare parts near by. Thus the problem of the Allied air forces was to inflict severe damage on nearly every usable air installation in France, and to do it so near D-day that there would not be time for the enemy to remedy the situation.
The master plan for Allied air supremacy depended upon three main programs: continued policing to keep the Luftwaffe in its reduced state; heavy bomber missions deep into Germany just before and soon after the invasion to discourage the Germans from removing their fighters to France; and wholesale attacks on airfields in France during the three weeks before D-day. If the bombing of air bases were accurate enough to remove vital installations, the shortness of time and German difficulties arising from the transportation chaos would compel the Luftwaffe to abandon any plan to utilize the best-located airfields. By waiting until the last three weeks before D-day to bomb airfields around Caen there would be less danger of giving away the invasion secret. Even so, attacks would be spread out in such a way as to conceal Allied concern with Normandy.
During April the tactical air forces of the AEAF conducted enough attacks on airfields outside the invasion area to produce some strain on the Germans and to gain practice. As yet, this type of target held a low priority, and the missions were often carried out when other objectives could not be bombed. So it was when small forces of B-26’s of the Ninth Air Force made nine attacks on six air bases during April. Most of the Ninth’s attacks were fighter-bomber missions, however, and during the month twenty-eight French airfields were bombed. Usually the pilots reported moderate success in damaging airfield installations, but results were difficult to assess and only on three occasions did pilots claim they had destroyed enemy aircraft on the ground.114 Meanwhile, the Eighth Air Force continued to attack air bases in France as part of its campaign to deplete the German Air Force. During the last week of April, Lightnings and Thunderbolts strafed and bombed various airfields in northern France while B-17’s, operating in forces numbering about 100 bombers, dropped heavy loads of bombs on airfields at Metz, Nancy, Dijon, Le Culot, Avord, Lyon, and Clermont-Ferrand.
By the beginning of May, Leigh-Mallory had his airfield program prepared and in the hands of the various air force commanders. Of the airfields and usable landing grounds in an arc 130 miles around Caen (designated Area I) 8 were assigned to RAF Bomber Command, 12 to the AEAF, and 20 to the Eighth Air Force. Area II extended from the 130-mile line to an arc 350 miles around Caen, reaching into Germany and the Netherlands, where 59 airfields were to be bombed by the daylight flying heavies of the Eighth and Fifteenth Air Forces. The program was flexible. Each air commander decided for himself when and how to hit the airfields on the basis of the general plans and current reports on target conditions issued by the AEAF.115 Fortunately, the air bases were grouped around Paris and Lille in such a fashion that the invasion plans were unlikely to be given away in the bombing pattern if all were bombed. Still, the Allies were to attack the airfields in Normandy on a deliberately lighter scale than the others. The only suspicious airfield from this standpoint was near Brest, which naval commanders insisted be bombed in order to prevent the German Air Force from working with submarines against the invasion fleet.116
On 11 May the campaign against airfields was begun in earnest by the Ninth Air Force, which was to drop the most tonnage of all air commands in the critical Area I. Thirty-seven B-26’s got good results at Beaumont-le-Roger and eighteen A-20’s were successful at
Cormeilles-en-Vexin. Several other forces had to be recalled because of bad weather. On 13 May, forty-two A-20’s bombed Beauvais airfield and three Marauder groups attacked Beaumont-sur-Oise, Chiévres, and Abbeville. Eight aircraft were damaged by flak but none was lost in the latter operation, a representative mission of the campaign with regard to cost. Weather and other commitments interfered for several days, during which significant attacks were carried out by fighters and light bombers on only three airfields, those at Creil, Gaël, and Chartres. Early in the evening of 19 May more than 200 P-47’s bombed airfields at Beauvais, Monchy, Breton, Abbeville, and Cambrai. On 20 May, seven groups of B-26’s attacked Denain, Évreux, Beaumont-sur-Oise, and Cormeilles-en-Vexin while a group of A-20’s bombed Montdidier. Two groups of B-26’s bombed Abbeville on the following day and Beaumont-le-Roger on 22 May. Also on 22 May, late in the afternoon, two B-26 groups attacked Beauvais and one struck Beaumont while three Boston groups were bombing Évreux and Cormeilles. So it went during the middle of May. The Ninth Air Force quickly completed most of its work of destruction. By D-day it had assaulted thirty-six airfields between Holland and Brittany.117 After the Marauders and Bostons inflicted major damage, fighter-bombers would rake over the air bases with strafing and dive-bombing attacks.
The Eighth Air Force had continued to devote marginal bombing effort to the Luftwaffe’s bases, but large-scale missions of 9 and 23 May 1944 marked its official entrance into Leigh-Mallory’s airfield campaign. Laon, Florennes, Thionville, St.-Dizier, Juvincourt, Orléans, Bourges, and Avord received the first blows from the Eighth, the highest tonnage falling on the Orléans airfield. More than 400 heavy bombers attacked airfields in the cluster around Paris on 24 May with generally good results. Potential Luftwaffe bases at Belfort, Nancy, and Brussels were bombed on the 25th.118 The Eighth Air Force missions were so effective that few repetitions were required, although Ninth Air Force and RAF fighter-bombers worked over all of the important airfields for good measure. By the end of May the Germans still showed no signs of trying to move their air units into France, and it was deemed safe to discontinue or reduce the attacks, even though the program was not completed. The Fifteenth Air Force bombed only two airfields in the south of France, and the Eighth and Ninth, except for last-minute bombings in early June, devoted their efforts to other purposes. By D-day airfields in Area I had received 6,717 tons, 3,197 of which
were delivered by the Ninth Air Force, 2,638 by the Eighth, and the remaining 882 by the RAF. In some respects the results were disappointing, for many vital installations remained undamaged and only four of the thirty-two targets in Area I were in Category A, with destruction so complete that no further attacks were considered necessary. German aircraft were still operating out of some of the bombed airfields, although they were mere fugitives which had to take to the air for safety every time an Allied air fleet approached. But the principal purpose of the program had been attained. The Germans did not have enough serviceable bases to put their air forces within good striking distance of the beachhead.119 The Luftwaffe fighter commander, Adolf Galland, recollected after his capture that most of the airfields he had planned to use were so bombed out that he had to improvise landing grounds elsewhere.120 Because of the ruined air bases and the transportation chaos, as well as of the danger of great British-American fighter fleets ranging over France, the Germans could not possibly move substantial Luftwaffe units to contest the invasion.
Perhaps the chief credit for keeping the German Air Force out of France before D-day belonged, as both Leigh-Mallory and Tedder said,121 to the Eighth Air Force, whose missions to vital German industrial areas made it dilemmatical for the enemy to remove any more fighters from the Reich, even for such an ominous threat as OVERLORD. As it turned out, German air opposition to the Normandy landings was astonishingly slight, far below the scale anticipated by the Allied air commanders. Indeed, one of the most remarkable facts of the entire war is that the Luftwaffe did not make a single daylight attack on D-day against Allied forces in the Channel or on the beaches.122
Breaching the Atlantic Wall
By the spring of 1944 the Nazis had built a wall of intricate and ingenious shore defenses along exposed beaches in the Netherlands, Belgium, and northern France. Most of the work had been performed by the Todt organization, which had constructed the Siegfried Line, under the supervision of the redoubtable Field Marshal Rommel. This so-called Atlantic Wall was supposed to dominate the coast sufficiently to keep Allied landing craft from approaching the continent, thus rendering a seaborne assault impossible. A good deal of its reputation came from propaganda designed to intimidate the western powers, and it is probable the Germans deceived themselves as to its strength.
Von Rundstedt knew the Atlantic Wall was much overrated. He said it had no depth and little surface; it was vulnerable from behind; and one day’s intensive assault could break any part of its front.123 But to Allied commanders it appeared formidable, and they were taking no chances. Fortunately, the Germans had left until last the construction of strong coastal defenses along the shore of Normandy. Only after an inspection tour by Rommel in March 1944 did the Normandy defenses receive much attention.124
The Allied planners were most concerned about coastal batteries along the Atlantic Wall, each of which held from two to six guns ranging in caliber from 105 mm. to 400 mm. Perhaps fifty of these batteries, it was estimated, would be functioning in Normandy by June 1944.125 The guns could command the sea approaches and inflict murderous damage on the assault craft. Camouflaged, cleverly located, and usually buttressed with steel and concrete, these coastal batteries would be exceedingly difficult to neutralize. Even if airplanes got through the flak they would have to place their bombs directly on the emplacements in order to achieve any effect. This being the case, OVERLORD plans prior to April 1944 did not provide for any serious air assault on the Atlantic Wall until a few hours before the invasion forces approached the continent. At that time, a gigantic air-naval bombardment would attempt to silence the guns by knocking them out or by killing and driving off the crews who manned them.
The air forces had expected to employ only medium, light, and fighter-bombers in this manner on D-day. But ground commanders calculated that 4,800 tons would have to be delivered, thus making it necessary to utilize Eighth Air Force and RAF heavies. Plans were accordingly made to send out Bomber Command missions on the night before the assault and for Eighth Air Force operations in the last thirty minutes before the landing craft touched far shore. Ground force requirements went a step further late in March 1944 when General Montgomery drew attention to the importance of making sure the coastal defenses were immobilized.126 Soon both the Army and the Navy were bringing pressure on the air forces to carry out experiments to determine whether some of the coastal batteries could be destroyed before D-day. If they could, not so much would depend upon the last-minute drenching of gun positions in what might be conditions of poor visibility on D-day.
The air leaders felt that too much was expected by the other services,
which made calculations on the basis of tonnages dropped rather than on accuracy of bombing.127 In April, however, it was discovered that eight of the major coastal batteries in the invasion area were temporarily vulnerable, since they had not yet been casemated and their lids were not fitted. Leigh-Mallory indicated his willingness to try to knock them out. Air Chief Marshal Tedder opposed expending any great strength in the attempt, as did Lt. Gen. Walter B. Smith, the SHAEF chief of staff. But the naval commander in chief, Adm. Sir Bertram H. Ramsay, urgently insisted that the unfinished batteries be bombed without delay.128
The greatest pains had to be taken to conceal from the Germans the special interest which the Normandy batteries had for the Allies. Thus two targets outside the area were chosen for each one inside it, a “wildly extravagant method,” as Air Chief Marshal Harris later termed it,129 but, of course, a necessary precaution, This meant that if all eight of the partially completed emplacements along the Normandy coast were bombed, sixteen completed batteries elsewhere would have to be attacked. The principal targets, both inside and outside the area, were the defenses near Le Havre, Calais, Dunkerque, Dieppe, Fécamp, Fontenay, Bénérville, Étaples, Houlgate, Pointe du Hoe, Ouistreham, La Bénérville, Maisy, and Gravelines. This wide distribution called for a considerable air effort, but so vital did naval and ground commanders regard the attempt that Leigh-Mallory gave it first priority. Naval commanders were to judge whether any of the batteries should be re-attacked.130
The Ninth Air Force and the Second Tactical Air Force undertook this campaign on 13 April 1944, with the former command destined to carry out a majority of the attacks. Ordinarily, one group of A-20’s or B-26’s would concentrate on a single battery. The enemy’s antiaircraft fire was usually effective, enough so that aircraft were occasionally lost and flak damage was frequently very heavy. During the remainder of April all twenty-four targets sustained bombings and 3,500 tons were dropped.131 While it was very difficult to arrive. at a sound estimate of damage, it seemed that fifteen of the batteries had suffered, and Leigh-Mallory was convinced that the attacks might do some good. Certainly the ground and naval commanders insisted that the bombings continue.
While the air forces were experimenting with the bombardment of the coastal defenses, various Allied officials became more and more
concerned about underwater obstacles which the Germans were found to be constructing off the Normandy shore, the last of the vulnerable coastal stretches to be so defended. These obstacles were steel, concrete, or timber stakes, often with mines or shells attached; ramps with mines or blades to tear the bottoms out of landing craft; and curved rails and pyramidical contraptions known as tetrahedra. Leigh-Mallory urged that fighters strafe the beaches while the workmen were putting up these obstacles during low-tide periods. This proposal, a tempting one, General Eisenhower finally rejected for the all-important reason of security.132 The Allies could not afford to indicate their concern with the Normandy beaches. But ground commanders continued to be troubled about the menace. Another danger loomed when Ninth Air Force bombers accidentally spilled some bombs into the water and set off a strange series of explosions.133 If this meant the Germans were mining all the beaches, the peril to landing craft would be greatly compounded. But the naval leaders were confident that they could surmount the difficulty and, as it happened, the enemy was unable to complete the mining before D-day.
The experimental attacks of April having indicated some success in damaging or retarding the completion of coastal batteries, operations of this nature continued until the invasion. Usually they had second priority among the AEAF’s objectives. In May, RAF Bomber Command joined the campaign and, toward the last, so did the Eighth Air Force. The Ninth Air Force sent out six groups of B-26’s and A-20’s on 4 May and five Marauder groups on 9 May to attack the batteries. Two groups bombed on 11 May and three groups on 12 and 13 May, each group concentrating on one battery. On 19 May six groups prosecuted the campaign, on 20 May two groups, on 22 May three groups, and on 24 May five groups. Altogether, it constituted a serious drain on the Ninth Air Force, but total airplane losses continued to be very light.134
The Eighth Air Force contribution to the coastal-battery campaign began on 25 May when fifty-four heavy bombers attacked Fécamp and St.-Valéry. General Doolittle had been encouraging the use of H2S radar blind-bombing equipment with an eye to possible cloudy conditions on D-day, and on the 25 May mission this equipment was employed-but with discouraging results. More success attended the efforts of the Eighth in massive raids of 2, 3, and 4 June, when 4,700 tons were dumped on coastal battlefields.135 It was RAF Bomber
Command which dropped the heaviest tonnage of all on the Atlantic Wall, some 14,000 tons, enduring severe losses in several instances to its slow, low-flying fleets of night bombers. Its most effective single mission prior to the night before the invasion occurred on 28/29 May, when 350 tons fell on guns commanding the proposed UTAH beach with excellent results.136 And the tactical air forces of the AEAF increased their attacks on the coastal defenses in the days just before the landing.
On the eve of D-day, 5,904 tons of bombs and 495 sixty-pound rocket projectiles had been directed at coastal batteries in the Normandy area, while 17,190 tons had been dropped on batteries outside the invasion sector. At the Allied air commanders’ conference of 26 May, Zuckerman had presented evidence that the bombings had not been so effective as expected. Subsequent bombings improved the picture, however, and Leigh-Mallory believed that at least twenty-one of the fifty-odd batteries in the NEPTUNE area had been damaged, aside from those outside the invasion area.137
Whether the air effort and bomb expenditure against coastal defenses prior to D-day had been worth while was never satisfactorily determined. Such an enormous weight of bombs and shells struck the batteries shortly before the invasion that it was impossible to segregate the damage as to air or naval, preinvasion or D-day. It was clear that the efforts to conceal the landing site had been highly successful, for the attacks on the Atlantic Wall had not shown the projected point of assault. It was also true that the scale of effort had been well within the capacity of the air forces and that losses had been very light except for Bomber Command. Reassuring as such factors were, however, they were more or less negative. Most postinvasion surveys concluded that the bombings of coastal batteries before and on D-day destroyed comparatively few gun emplacements, as the air commanders, guided partly by experience in the assault of 1943 on Pantelleria,* had predicted. But the unbalancing and dislocation of guns, the demoralization of their crews, and delays to the completion of the Normandy beach batteries were accomplishments of no small nature.138
The Germans had constructed a very extensive system of radar coverage from Norway to the border of Spain. Between Ostend and Cherbourg their system was especially thick, with major stations every ten miles supported by a less intensive but highly efficient network inland. The Allies were well informed about the location, type, and
* See Vol. II, p. 432.
importance of these stations, which could detect airborne and seaborne forces and could set in motion both coastal and flak defenses. Consequently, they considered from the earliest days of invasion planning to the last moment methods of throwing the entire system into confusion. It would be impossible to destroy all of the radar installations by bombing because of their number and stout defenses. Also, it should be unnecessary if countermeasures could jam most of the stations. But the installations between the Channel Islands and Ostend would be difficult or impossible to neutralize by jamming. These stations were really the most important ones, since they could furnish good readings on ships, control coastal guns, and assist the enemy’s night fighters in locating airborne forces.139 Thus it was essential to try to obliterate them by air attack.
The ever present consideration regarding concealment of the landing site made it prudent to plan on bombing two radar installations outside the assault area for each one within it. Most of the attacks were carried out by Second TAF Typhoons, although the Eighth and Ninth Air Forces participated on several occasions and RAF Bomber Command distinguished itself in one brilliantly successful mission. The first attacks took place on 10 and 18 May against the so-called Hoarding long-range aircraft reporting stations. On 25 May the campaign became intense when 42 sites containing 106 installations were assigned for bombing.140 The tactical air forces of the AEAF flew 16,668 sorties against these targets, sometimes using Spitfires and Typhoons for dive bombing, Typhoons for firing rocket projectiles, or light and medium bombers for bombing. And the heavies put several stations out of action in precision attacks involving a small number of aircraft. These missions proved very dangerous and costly but the Allies did not have to abandon the program, a possibility that had been reckoned on when it was about to be undertaken.141 Because of the high casualties, however, Leigh-Mallory restricted the bombing to twelve targets in the Normandy area after 29 May, six of which were chosen by naval authorities and six by air authorities. All of them were attacked before D-day.142
The damage inflicted on the radar network was of the utmost importance. Nearly all of the installations in the invasion area were badly crippled or wiped out. A devastating attack on a station near Cherbourg removed, as the Allies later discovered, the headquarters of the Nazi signals intelligence and reporting service for northern France.143
A USSTAF appraisal regarded as conservative estimated that the bombings had reduced the effectiveness of the enemy’s radar system in the crucial area to 18 per cent.144 When ingenious radar counter-measures were put into effect just before the landing, the figure fell to 5 per cent.145 The Germans were therefore blind to Allied movements toward the Atlantic Wall, and they were utterly confounded about the nature and intentions of the invasion forces. They were surprised in Normandy, and for days afterward they possessed no trustworthy means of detecting the approach of air and naval fleets.
The Beginning of the Campaign against Oil
During the climax of the preinvasion bombings the Eighth and Fifteenth Air Forces launched what was to become their most rewarding campaign in the strategic air war, the destruction of enemy oil production. Since the start of the war Germany’s oil position had been precarious, although it was never as desperate as Allied planners usually imagined. In the last full year of peace, 1938, Germany had consumed 7,500,000 tons of petroleum products, two-thirds of which she imported. When she invaded Poland in September 1939, her oil reserves were so low that only six months of operations could be permitted. Lightning campaigns and diplomatic victories soon brought the resources of France, Hungary, Rumania, and other countries into Nazi control, however. Drastic measures to restrict consumption were helpful, and the Germans began to develop a huge industry to produce synthetic oil from coal by means of the Bergius and Fischer-Tropsch hydrogenation processes. In 1943 these synthetic oil plants turned out more than 6, 180,000 tons of petroleum products, and 2,000,000 tons of crude oil were drawn from Rumania and Hungary. While their reserves were always low, the production of synthetic oil was rising so rapidly by early 1944 that the Germans could contemplate the future with some confidence.146
As early as 1940 the British had planned seriously to attack German oil facilities, and American interest had frequently swung to this possibility. But by May 1944 only 1.1 per cent of all Allied bombs had been directed at petroleum targets.147 The reason why the Allies delayed opening an oil campaign so long was simply that they did not have sufficient air forces available. Oil production centers were widely scattered about in the Axis countries in more than eighty different localities, many of them entirely out of range before the Fifteenth Air Force
was established in Italy. Components of the oil complex were four or five times more numerous than aircraft factories and eight times more numerous than ball-bearing production centers.148 Not until early 1944 did the Allies possess, in the Eighth and Fifteenth Air Forces and RAF Bomber Command, enough heavy bombers to undertake a systematic attack on oil, and first they had to overcome the dangerously resurgent Luftwaffe. Then there were CROSSBOW commitments and, of course, the unexpectedly large demands of the preinvasion bombing campaigns. On its part, the Fifteenth Air Force expended most of its effort in POINTBLANK, assistance to the land campaigns in southern Europe, and political raids on Balkan capitals. As late as January 1944 air commanders in both London and Washington, fortified with the views of the operations analysis section of the Eighth Air Force, agreed that oil should receive no priority in the strategic air war.149 There were too many other things to do.
As the victorious nature of POINTBLANK operations became evident during February 1944, considerable interest developed in attacking oil production. The Joint Intelligence Committee,150 Lt. Gen. Brehon B. Somervell of the Army Service Forces,151 and the American Embassy’s Economic Warfare Division suggested that the time was opportune to undertake an oil offensive. Most significant of all, General Spaatz came to the conclusion during that month that a strategic attack on enemy oil would flush the German air force and would contribute more to the success of OVERLORD than any other type of campaign within the capabilities of the heavy bomber forces. In his Plan for the Completion of the Combined Bomber Offensive, which he presented to General Eisenhower on 5 March 1944 as an alternative to the AEAF transportation plan,* Spaatz drew attention to the great strides the Germans were making in producing synthetic oil. In the next six months, the USSTAF commander estimated, the enemy might obtain 8,600,000 tons of liquid fuels and lubricants, which would largely relieve him of his embarrassment with respect to oil requirements. Approximately 90 per cent of this output was accounted for by fifty-four crude-oil refineries and synthetic petroleum plants, of which twenty-seven were especially important. These twenty-seven centers had been grouped about Ploesti, in Silesia, and in the Ruhr in the overconfident expectation that the Luftwaffe could protect them. By destroying them the Allies might deprive the Germans of half their gasoline supply.
* See above, p. 76.
If all fifty-four centers were attacked successfully, German oil production might fall to zero by September 1944. The twenty-seven-plant objective, Spaatz contended, was already well within the capabilities of the Eighth and Fifteenth Air Forces.152
Several obstacles stood in the way of an oil offensive at that time. General Eisenhower had before him the recommendations of Leigh-Mallory, Tedder, and many others that the railway system of western Europe should be destroyed in a long-range bombing campaign. The requirements of CROSSBOW were large and growing. Air Chief Marshal Harris of Bomber Command was opposed to the oil project.153 In AAF Headquarters, Arnold and Maj. Gen. Barney M. Giles supported Spaatz’s ideas in general but felt they were premature for consideration by the Combined Chiefs of Staff, that it was up to Spaatz to convince Eisenhower before anything was done in Washington.154
There was, however, a chance to open the oil campaign by dispatching the Fifteenth Air Force to attack the crude-oil refineries around Ploesti, already attacked in the famous mission of August 1943. On 17 March 1944, Arnold notified Spaatz that the Combined Chiefs had no objection to his ordering attacks on Ploesti at the first opportunity,155 but even so it was thought wise to begin the undertaking surreptitiously under the general directive which called for bombing transportation targets supporting German forces that faced the Russians, who were then breaking into Rumania.156 Such transportation targets stood in the vicinity of Ploesti, and on 5 April 1944 the Fifteenth Air Force administered an attack on the marshalling yards there with 146 B-24’s and 90 B-17’s. Most of the 588 tons of bombs, with more than coincidental inaccuracy, struck and badly damaged the Astra group of refineries near by. The Americans did not proclaim the opening of the oil offensive, even in their secret intelligence summaries, but on 15 and 24 April large forces of heavy bombers again attacked Ploesti marshalling yards in the expectation that most of the bombs would produce “incidental” damage to oil refineries. This damage occurred, and to a very encouraging extent.157 Hitler was soon referring petulantly to the whining of the Rumanians about these air attacks,158 and the Americans were delighted with the results. By 4 May, MAAF headquarters fortified the authority for the Fifteenth Air Force’s oil missions by granting permission for them to continue if tactical considerations allowed.159
While the Fifteenth Air Force was inaugurating the oil campaign, the way was partly cleared for Eighth Air Force participation. Spaatz
fought hard for his plan of 5 March 1944 and against the long-range transportation plan to bomb rail centers. The cardinal issue, as Spaatz made clear at the time and after the war,160 was to draw the German Air Force into the skies. He contended that it would expend itself against heavy bomber fleets engaged in attacking oil installations but would conserve its strength while targets of such dubious value as rail centers were being bombed, and he was right. But General Eisenhower’s decision in favor of the transportation plan on 25–26 March did not rule out altogether the possibility of attacking oil. Five days after the supposed settlement of the oil-rail center controversy, Spaatz proposed that thirteen synthetic oil plants in Germany be attacked as third priority, coming after the German Air Force and the rail centers. In order to do this the Eighth Air Force and Bomber Command would bomb rail centers by daylight. Also during daylight the Eighth would attack oil plants in the Ruhr while RAF heavies would go to the Stettin vicinity at night.161 This proposal the RAF rejected because its leaders were unwilling to expose their heavy bombers at that time in daylight operations and, of course, because most of them were not then convinced of the advantages of an oil offensive.
There was still another possibility. Eisenhower’s directive to the strategic air forces on 17 April 1944 gave the German Air Force first priority in USSTAF target listings. The Luftwaffe used oil products and, as AAF Headquarters pointed out,162 attacks on oil installations could come under the general heading of POINTBLANK without disturbing the Combined Chiefs or the British with efforts to change the existing system of priorities; moreover, the destruction of German fighters which rose to defend the oil plants was undoubtedly a major purpose of the Eighth Air Force. Thus the Eighth Air Force could destroy oil targets, at least as an experiment, while pursuing POINTBLANK, and the Fifteenth Air Force could bomb them under the subterfuge of attacking railway objectives.163 General Eisenhower, who leaned heavily on Spaatz in air matters, granted verbal permission on 19 April for the bombing of German oil targets on the next two days of good visual conditions. The supreme commander emphasized, as did Spaatz, that the fundamental purpose was to determine the willingness of the Germans to send their fighters against attacking bombers.164 Somehow it seemed important to the two U.S. leaders not to go on record as taking the initiative in opening this new offensive, which soon would be the pride and chief concern of the strategic air forces. Tedder, who was
in charge of strategic air operations for OVERLORD, momentarily jeopardized the project by insisting upon CROSSBOW attacks by the Eighth Air Force instead of the oil missions. But a visit of Spaatz to his office on 20 April resulted in a compromise to the effect that one day’s effort would be devoted to CROSSBOW, and that the two days of good bombing weather would remain open for the oil plant assaults.165 Spaatz accordingly directed Doolittle to plan on attacking as many oil targets as possible in central Germany.166
On the following day, 21 April 1944, Doolittle had 864 heavy bombers and 1,040 fighters scheduled to begin the oil offensive.167 But rapidly deteriorating weather conditions at the bases and target areas compelled him to cancel the mission. Not until 12 May were conditions suitable for the great experimental attack, one which the Germans had been dreading almost above everything.168 They had foolishly grouped their main synthetic oil plants together, and by now they had no strong Luftwaffe to defend them. Their shortsightedness proved painful on the 12 May mission and during the numerous attacks which followed. On this occasion, 15 combat wings involving 935 heavy bombers, escorted by Eighth and Ninth Air Force and RAF fighters, took off for what was to prove a historic operation.169 The aircraft proceeded to a point south of the Ruhr, skirting the highly defended sites in that area and around Hannover and Brunswick, and then flew east and northeast toward the target area. Near Frankfurt the GAF rose to intercept the leading combat wings, and the enemy fighter pilots exhibited their usual aggressiveness once they were off the ground. Between 150 and 200 enemy aircraft attacked, mostly in mass, using saturation tactics. In some cases 30 German fighters came in abreast, firing savagely and even ramming the B-17’s. One of the combat wings lost half its bombers and became thoroughly disorganized. Before further harm was done, escorting P-47’s and P-51’s came to the rescue and the bombers proceeded to their targets. Most antiaircraft fire was of moderate intensity. More than 800 heavies attacked, dropping 1,718 tons on the synthetic oil plants at Zwickau, Merseburg-Leuna, Brüx, Lützkendorf, Böhlen, and other cities. The targets were slightly obscured by low clouds and ground haze. During the withdrawal phase a force of 50 German twin-engine fighters pressed determined attacks against the bombers for almost a half-hour and smaller groups of single-engine fighters attempted interception. In all, the Eighth Air Force lost 46 heavy bombers on this mission, and 10 Allied fighters failed to return.
Bomber crews claimed 115 enemy aircraft and fighter pilots 75. Certainly the professed objective of the mission was attained: the German Air Force had reacted vigorously to the attacks on oil plants and had suffered severe losses.* More important in the long run was the fact that all of the targets were damaged, some of them very heavily. Brüx, Rohlen, and Zeitz were knocked temporarily out of operation, and the bombing at Merseburg-Leuna happened to destroy a building in which experiments were being conducted with heavy water for Germany’s atomic-bomb project.170 It was an excellent mission, despite the heavy loss of bombers, and an auspicious opening of the Eighth Air Force campaign to deny the Germans oil.
Heavy OVERLORD commitments and weather conditions kept the Eighth Air Force away from oil targets for more than two weeks after the notable operation of 12 May. But the Fifteenth Air Force was by now well launched in the oil offensive. Its chief target in this system was the invaluable cluster of crude-oil refineries at Ploesti, the source of approximately one-fourth of Germany’s petroleum even when, as at that time, it was not in full operation. The Fifteenth also included smaller crude-oil targets in Austria, Hungary, and Yugoslavia while its companion air force, the RAF 205 Group, filled the Danube regularly with mines to interfere with barge shipments of oil to the Reich. These Danube mining operations proved more effective than the Allies apparently realized.171 On 5 May the Fifteenth’s bombers, almost 500 strong, fired many of the installations around Ploesti and encountered, as might be expected in view of Germany’s need for the refineries, very intensive antiaircraft fire and more than 100 fighters. On 18 May 700 Fortresses and Liberators flew against Ploesti but two-thirds of them could not attack because of adverse visibility conditions. Good results were achieved on 31 May, when 460 heavies of the Fifteenth bombed the refineries, and on 6 June, when 300 B-24’s carried out a highly successful attack.172 Ploesti would remain the favorite target
* As usual, an irreconcilable discrepancy is evident between American calculations and captured German records, and smaller disparities among the several types of data kept by the Nazis. While the Americans claimed 190 enemy fighters on the 12 May 1944 mission, one German source acknowledges that 50 were lost and 10 were missing, and another admits of only 39 lost for a two-day period, 12–13 May, all over the Reich. On the other hand, the Americans are surely correct in their secret reports when they state that 10 US. fighters were lost; yet the Germans listed 81 for sure and 10 probables, all apart from their mendacious public announcements. (German statistics on German fighter reaction to Anglo-American bombing attacks. Science Memo No. 15, ADI[K] [USAFE]; Gesamtsverluste der fliegende Verbande, in German High Command Quartermaster collection now in the British Air Ministry, AHB 6.)
of the Fifteenth Air Force until August 1944, when Russian land forces moved into the ruins. And soon after D-day aircrews of the Fifteenth would become very familiar with the route to the synthetic oil plants of eastern Germany.
The Eighth Air Force returned to the oil offensive on 28 May 1944, when more than 400 heavies bombed synthetic oil plants at Ruhland, Magdeburg, Zeitz, Merseburg-Leuna, and Lützkendorf, all of them damaged targets still suffering from the raids of 12 May. Results were good everywhere.173 Zeitz was put out of operation again. Later, a German prisoner reported that Italian conscript workers had helped spread the flames at the giant Merseburg-Leuna plant and that Goebbels and Speer had rushed to the stricken area to deliver inspirational speeches to the demoralized German laborers.174 On 29 May the Eighth sent 224 Liberators to the vast and distant synthetic oil establishment at Pölitz and damaged it severely.175
On both the 28 and 29 May missions the Eighth Air Force had met serious Luftwaffe opposition and had lost forty-nine heavy bombers on the two operations.176 Undoubtedly, the German high command was profoundly aroused by these attacks on the oil installations and had ordered the Luftwaffe to resist them with all its power. Other heavy bomber missions into the Reich during the weeks before the invasion pinned down Germany’s fighter units and overwhelmed them whenever they attempted to interfere. Notable were Eighth Air Force attacks of 18 April against the Berlin area, of 24 April against Friedrichshafen, of 26 April against Brunswick and Hannover, of 29 April and 7 and 8 May against Berlin. The Fifteenth Air Force missions to Ploesti and to Vienna (10, 24, and 29 May) likewise served to discourage German removal of fighter units to meet the threat of OVERLORD. These strategic assaults on the Reich were closely related to the fact that the invading forces were not disturbed by the GAF on D-day. During the spring of 1944 Allied fighter pilots and gunners so increased their pressure on the enemy that Goering received warning in mid-May of Luftwaffe pilot losses critically in excess of replacements.177 An American appraisal of German records indicates that aircraft losses sustained by the GAF, including planes damaged to the point of requiring replacement, reached their peak in April, the total figures for February being 1,432, for March 2,012, in April 2,540, and during May 2,461.178
Forcing the Luftwaffe to remain in Germany and inflicting heavy
losses on it there were important enough, but the injury wrought on oil production centers was exceptionally painful to the enemy. The first two months after D-day would not reveal Germany’s plight with regard to oil supplies, but from August 1944 on, all German forces would be greatly hampered by lack of fuel and lubricants. As soon as the synthetic plants were attacked the enemy correctly gauged the Allied intention for a continued offensive and comprehended how serious for the Reich it was likely to be. Albert Speer afterward said that the oil attacks of May 1944 brought about the decision of the war.179 Only 5,166 tons of bombs were aimed at oil targets during that month. Yet German production for June fell sharply, amounting only to half the figure for March output, and the Germans, appalled at the vulnerability of Ploesti and of their synthetic oil plants, undertook desperate measures to maintain a flow of fuel to their armed forces.180 It was only the beginning, and both the Allies and the Germans knew it. USSTAF was, of course, jubilant at the effectiveness of these first attacks. Eisenhower was convinced, and the British were won over to the oil campaign by the last of May.181 On 4 June 1944, an ETO press release would proclaim publicly the oil offensive, and on 8 June, with OVERLORD begun, Spaatz would place oil in first priority for the U.S. strategic air forces. The campaign was off to a splendid start.
Air Reconnaissance before the Invasion
The reconnaissance units of all air forces were heavily employed in vital activities during the preinvasion period. In addition to the normal photographic coverage of POINTBLANK targets in Germany and watchful tactical reconnaissance of enemy activities in France and the Low Countries, exact information had to be obtained for the impending OVERLORD operation. Considerations of security dictated the scattering of reconnaissance effort over western Europe. AEAF headquarters supervised the general program for reconnaissance related to the invasion and adjusted air requirements with those of 21 Army Group and the naval forces as well as with those of SHAEF. Furthermore, the photographic units of USSTAF were brought into a close working relationship with the AEAF so that coverage would be complete and efficient.182 The Allied air forces were somewhat understrength in photographic and tactical reconnaissance aircraft but by the spring of 1944 they had much experience and good methods.183
As D-day approached, tactical reconnaissance missions took on an
especially urgent character. The Ninth Air Force and the Second TAF flew at least eight missions daily, at times in weather regarded as too hazardous for ordinary air operations, over the area in France north of the Seine. Partly this was to create such a broad reconnaissance pattern that our actual intentions would not be revealed, but the pilots often reported via radio-telephone the movement of trains and other targets which fighter-bombers could attack on short notice. And they would relay timely information on troop movements or activity in repairing bridges and railroad tracks, and sometimes would make photographs of targets when assessment was needed at once. The Ninth Air Force alone dispatched more than 400 aircraft on such visual reconnaissance missions between 15 May and D-day.184
It was photographic rather than tactical reconnaissance which assumed the more importance for the invasion leaders as D-day drew near. Already having mosaics of the entire coast line of western Europe and pictures taken of the Normandy and Pas-de-Calais beaches from 3,500 feet, they required still more specific data. Accordingly, the Ninth Air Force and the Second TAF sent out aircraft to photograph the proposed assault beaches from varying distances and at wave-top height so the unit commanders would know exactly what their objectives would look like from several miles out, at 1,500 yards, and from the shore line as they moved in on the crucial day of the landing. Also, the unarmed reconnaissance airplanes made photographs of every possible yard of the beaches and areas immediately behind them, zooming and swerving to avoid cliffs and sand dunes, in order to provide ground force officers with up-to-date information about the shore they would soon find themselves on. It was necessary, moreover, to make low-altitude photographs of the proposed airborne landing areas for assistance in planning these operations.185 Here, as elsewhere, two missions were prescribed for other areas for each one over Normandy.
The 10th Photo Reconnaissance Group of the Ninth Air Force performed eleven extraordinary missions, all as dangerous as they were vital. The exact nature of the underwater obstacles and beach barricades not being known to the assault commanders, it was decided to make photographs of the shallow water and beaches from altitudes as low as fifteen feet. The photographs obtained were of the utmost value, since they revealed which of the obstacles were timber and which were steel or concrete, how the mines and shells had been affixed, where the concentrations were worst, and how deeply they were anchored. The
assault commanders could therefore plan precisely how to avoid or remove the obstacles as they moved toward the French coast. One pilot was killed in these so-called Dicing missions, and the group won much praise and a Presidential unit citation.186
In these reconnaissance and other missions it was necessary to avoid tipping the enemy as to the exact nature of Allied plans for the invasion. He could scarcely be fooled as to the fact that one was to occur, for the enormous build-up of Allied forces in the United Kingdom, the intensification of bombing operations, and the inevitable speculation in Britain and America informed him of the chief intention of his foes. But plans built essentially on the common-sense rule of avoiding such a concentration of the air effort as to betray Allied intentions served well the purpose of achieving for Eisenhower’s forces on D-day the advantage of tactical surprise. Indeed, the overwhelming bulk of German divisions in the west was deployed to the north of Normandy in the expectation that the attack would come in the Pas-de-Calais, and was cut off from Normandy by the chaotic condition Allied air attack had brought upon the intervening transportation. The enemy, as General Spaatz was able to report, had been thrown completely off guard.187
Though the air forces could hardly claim full credit for this achievement, the responsibility rested heavily upon them and added greatly to the burden of their several preinvasion tasks. In this as in the transportation campaign, the airfield attacks, the neutralization of the Atlantic Wall, reconnaissance, and the steady blows at Germany’s industrial vitals the Anglo-American air forces did more than facilitate the historic invasion of 6 June 1944. They made it possible.
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