By 10 May 1940, when Germany invaded France and the Low Countries, 228 D.520s had been manufactured, but the French Air Force had accepted only 75, as most others had been sent back to the factory to be retrofitted to the new standard. As a result, only GC I/3 was fully equipped, having 36 aircraft. They met the Luftwaffe on 13 May, shooting down three Henschel Hs 126s and one Heinkel He 111 without loss.
The Potez 637 was one of the more modern aircraft in the reconnaissance groups, but losses were heavy. Production of this variant was limited, and the Potez 63.11 played just as important role in these groups. The Potez 63.11 was also the most important aircraft in the army co-operation units, where it suffered heavy losses, mostly to ground fire and on the ground (although managed to hold its own against German fighters). By 1940 the entire family was outdated, with the lack of engine power.
More than 700 Potez 63.11 were delivered by June 1940, of which more than 220 were destroyed or abandoned, despite the addition of extra machine gun armament; the heaviest losses of any French type. The Potez 63.11 continued in service with the Vichy air force and with the Free French forces in North Africa seeing action with both. Production was resumed under German control and significant numbers appear to have been pressed into service by the Germans, mostly in liaison and training roles.
To some, the task now facing France seemed hopeless. The Dutch and Belgian Armies had been defeated, only one British division remained in the front line, and one third of the French Army had been lost. On 10 May, the Allies had outnumbered the Germans. Now, the French stood virtually alone and outnumbered in every respect. There seemed to be good reason for French pessimism.
The short-term prospects of the French may have been bleak, but if the Army could hold on, all was not necessarily lost. Fresh divisions were already arriving from North Africa and the French divisions plucked from the Dunkirk beaches were heading back to France. Better planes were on the way and production was rising rapidly. The delivery of nearly 200 modern fighters was expected in June and by August, it was hoped that monthly output would have risen to 400, which was far more than the German aircraft industry was turning out. Even more significant was the improved quality of these fighters. On 12 May, the HS 12Y-51-powered Dewoitine D.523 achieved 562 km/hr and two days later, a similarly powered Arsenal VG-35 managed 590 km/hr. French fighters would finally have the speed to intercept German bombers with ease and the ability to take on German fighters on equal terms. The delivery of the first 200 HS 12Y-51 motors was expected in June and deliveries of the D.523 were due to begin in July. Production of bombers was also rising fast. French factories were expected to build over 200 in June and with deliveries from the United States also increasing, very soon, some 500 would be becoming available each month. However, all of this would mean nothing if France could not stem the German tide; to do this, everything available would have to be thrown into the struggle.
The brief lull in the fighting on the Somme and Aisne fronts as the Germans concentrated their efforts on the Allied forces surrounded at Dunkirk gave the French a brief opportunity to reflect. Valuable lessons had been learned and Georges was anxious to apply them. He was particularly struck by the speed with which German commanders could get air support; he estimated bombers could be over a target within fifteen minutes of the request being made. He claimed this feat was only possible because the German Army and Air Force were under a single commander. This was not quite the case, but they were part of the Wehrmacht, which acted as one. Georges’s comment was clearly a swipe at the whole concept of an independent Armée de l’Air. In truth, however, it had been this independent Air Force that had argued for tactical close air support and the Army that had been reluctant to incorporate the idea into its thinking.
Georges now accepted the enormous impact the direct intervention of bombers on the battlefield could have. Quite correctly, however, he observed that although the psychological impact had been great, the actual physical harm done was often limited. Fighter units had to be called in quicker; in terms no French general would have trouble understanding, he explained how rapid fighter intervention against bomber attack was just like a counter-artillery barrage. He was, however, careful not to lay all the blame for the collapse of French Army formations on the Air Force. He recognized that the Army had simply not done enough to prepare the troops for the shock of aerial bombardment. The reaction of French soldiers had been far too passive and this had bred a feeling of helplessness. He urged all commanders to instil in their troops the need to turn all weapons on the attacking aircraft. He pointed out that French aircraft were often returning from missions riddled with small arms fire. French troops had to be trained to take a more active part in their own defence. This would reduce the accuracy of German bombing, lower the morale of German aircrews, increase Luftwaffe losses, and, most importantly of all, lift French morale.
The role of the GAO observation groups also came under close scrutiny. As Têtu now freely admitted, these units had played virtually no part in the fighting. Seven months before, the commander of the observation forces had suggested that the crews of the grounded bomber groups in the rear should be retrained as reconnaissance pilots. Now, he was proposing removing all observation squadrons from army corps, creating fewer larger units under his direct control and using surplus crews to reinforce bomber and fighter units.
In the last three weeks of May 1940, the French made more progress towards a more modern air force than they had managed in the previous decade. The Army now appreciated that the bomber was a battlefield weapon, and the need for more fighters had been hammered home. It was now accepted that a disproportionate amount of effort had been put into observation squadrons at the expense of other branches of the Air Force. The Army was still suspicious of Air Force intentions, and with the way d’Astier had been running air operations, they had good reason, but there was agreement about the need for more centralised control of the Air Force at a higher level of command.
While all this was now plain to the French High Command, it would be some time before these new ideas filtered through to commanders in the field and time was something the French did not have. On 29 May, the outlines of a German offensive across the Somme and Aisne were already being drawn up. The German Army had so far suffered surprisingly light losses, but advances of several hundred miles inevitably imposed considerable wear and tear on equipment. Hitler, however, was determined not to give the French any time to recover and there would only be the briefest of rests before the attack was renewed. The next offensive would be launched on 5 June. The stakes were high. If it failed, the Germans would be forced to give their units time to rest and refit. This in turn might give the French time to complete the re-equipment of their Air Force, rearm the French troops that had escaped at Dunkirk, and put into practise the lessons they had learned. On the other hand, an immediate German success on the Somme and Aisne might lead to the disintegration of the French Army and the defeat of the nation. The French felt if they could just hold the next offensive for a week, the situation would begin to look very different.
Once any attempt at linking up with the forces in the northern pocket had been definitively abandoned, Weygand turned his attentions to strengthening the defensive lines along the Aisne and Somme. The French Air Force was required to protect French reinforcements disembarking at railheads in the rear, disrupt the German build-up on the Somme and Aisne, and support French efforts to eliminate the bridgeheads at Abbeville, Amiens, and Péronne. From the 26th, the Luftwaffe was concentrating on Dunkirk and enemy air activity over the southern front was light. On the last three days of the month, the same bad weather that helped the Dunkirk evacuation succeed also brought French aircrews a welcome respite.
The French used this time to refit their squadrons as best they could. The M.S.406 was to be replaced as quickly as possible. After losing all its M.S.406s on the 16th, GC II/6 moved to the Châteauroux Bloch MB.152 plant; between 23 May and 1 June, the group took delivery of thirty-four as they came off the production line. The pilots flew patrols in defence of the factory as they got used to their new mounts and demonstrated they were fully operational by claiming four He 111 bombers that attacked the factory on 5 June. Other groups converted even more rapidly. On 29 May, GC III/2 handed over its surviving M.S.406 to other groups, and between 31 May and 5 June, the group took delivery of thirty recently arrived Curtiss H75 A-3. The unit flew its first operation with the plane on 6 June. This was not nearly enough time to become fully familiar with a new plane, but it was the sort of urgency that France would need to have any chance of surviving. GC II/7 received thirty-five D.520s between 20 and 29 May and flew its first mission with the fighter on 1 June. GC III/3 got its first D.520 on 25 May and flew its first mission with the plane on 5 June.
With the reduced aerial activity, replacement Bloch MB.152 and Curtiss H75s reaching squadrons for once exceeded combat losses and there was time to repair damaged machines. Even so, most H75 and Bloch groups had fewer fighters than on 10 May. Dewoitine groups at the front were particularly short of equipment as nearly all new output was being used to convert M.S.406 units. At least the few remaining M.S.406 groups had no problems with reserves; the remaining units were turning away machines being offered to them by groups converting to new types. By the beginning of June, the number of fighters available had risen to 356. French losses among fighter pilots amounted to 160 killed, wounded, or captured, but these had been largely made good. A total of 175 pilots arrived from training schools in May. In the first days of June, another fifty fighter pilots arrived and another 100 were expected to become available in a matter of days. These were supplemented by some instructors hastily called back to front line duties to see France through the crisis.
Bomber units were also benefiting from increased production. There were still no fully operational Amiot 351/354s, which meant the bomber could still only be used by night at low level. Groupement 6 returned to the front on the 28th after a week’s rest and refit. At the beginning of June, there were six LeO 451, four Breguet 693, four Martin 167, and two Douglas DB-7 groups available for day operations, with a paper strength of around 200 bombers, although only a half, at most, were serviceable at any one time. Another eight groups were available for night operations.
The GAO and reconnaissance units had lost around sixty Potez 63.11 reconnaissance planes in combat since the beginning of the campaign, but around 100 more had been destroyed on the ground or abandoned. Eighty replacements helped restore Potez strength to around 130, of which eighty-five were serviceable, an improvement on the forty-eight that had been available on 21 May. Those GAO still at the front contributed another 120, of which around seventy were serviceable. However, there was a reluctance to risk any of them if fighters were not available for escort duties. The Bloch MB.174 could operate without an escort, and Vuillemin ordered a special effort to be made to ensure as many as possible were made available to front line units but switching production from the Bloch MB.174 to the Bloch MB.175 meant deliveries of new machines had virtually ceased. On 5 June, there were only nine serviceable Bloch reconnaissance planes along the entire front. Interestingly, older planes like the Mureaux reconnaissance machines were not even listed. France was not in a position to be so cautious about which planes it used.
The shortage of modern planes was chronic but there was no shortage of aircrews. French naval squadrons had been heavily involved in the fighting, and they now expected a proportion of the modern planes that were coming off the production lines. On 31 May, the first ten Dewoitine D.520s were handed over to re-equip one of their four fighter squadrons. The Navy also got its first LeO 451s and Martin 167s. Large numbers of Belgian aircrews were now joining the Poles and Czechs in the rear. The aircrews of the 1st, 7th, and 9th Army observation squadrons sent to the rear were also still waiting for something to fly.
More Poles and Czechs were finding their way to front line squadrons. On 28 May, eighteen Polish fighter pilots were posted to front line squadrons. On 3 June, another thirty-three Poles followed. There was now far less resistance to the idea of units manned entirely by foreign personnel. On 24 May, the first Polish bomber unit was finally formed and was expected to become operational with the LeO 451 in mid-June. Other Poles were to begin training on Martin 167s. On 1 June, the morale of the Czech contingent was given a boost by the signing of an agreement finally allowing an independent Czech Air Force within the framework of the French Air Force, along the lines of the agreement already made with the Poles. Two Belgian squadrons began converting to the LeO 451, but the aircrews from eleven more were waiting for something to fly. On 4 June, another 100 Polish fighter and fifty bomber pilots completed their training. At a time when units were being converted to new types and thrown back into action within days, it was not too late to make use of these pilots, if planes could be found for them to fly.
The French still held out hope that even at this late stage, the United States might save the day. Since 23 May, the French, apparently armed with a detailed list of planes held in American stores, had been preparing a request for more American help. By the time it was made, it had become a frantic appeal for anything, however obsolete, the Americans could send. Aware of the many American planes the French already had, but through lack of vital equipment could not be used, Reynaud made it clear that they had to arrive fully armed and ready for use. Astonishingly, within a couple of weeks, the Americans had gathered together ninety-three obsolete Northrop A-17A attack bombers and fifty Curtiss SBC biplane dive-bombers and the first batch left for France on 16 June.
Did the French have to wait for the Americans to go through their reserves and ship what they could find across the Atlantic? Should the French Air Force have looked more closely at their own stored obsolete equipment? The French Army was already hauling obsolete mothballed 75-mm guns out of stores and dispatching them to the front to be used as anti-tank guns over open sights. Soon after the Germans launched their attack, Vuillemin had ordered storage units to make available as many fighters and bombers as possible. Bloch MB.151s and Koolhoven F.K.58s had been hastily made serviceable and used to equip rear defence flights, but nothing older than these relatively new fighters was considered. The plea for bombers saw much effort put into preparing old Amiot 143 and Bloch MB.210s for combat. Indeed, so many were arriving at the Avord air base, they did not know what to do with them and told the units to stop sending them. These ungainly, difficult to fly bombers were better than nothing, but perhaps it would have been better to focus effort on cannon-armed Dewoitine D.501and D.510 single-seater fighters for ground strafing, or Mureaux reconnaissance planes for bombing. Perhaps it was even time to see if the old Potez 25s could be used like the Dutch used their Fokker C.Vs. It seems, however, that to the very end, the French default preference was large multi-seaters.