Decisive Offensives I: Oil, May 1944-September 1944
Up to the spring of 1944 the strategic air offensive had not struck a decisive blow against Germany. It had done much damage; it had forced the Nazis to commit enormous resources to repairs and defense; it had slowed work on new weapons, and it had defeated the Luftwaffe. But it had not critically hurt the German economy, or even seriously interrupted production of a vital item. This was not clear at the time; the Allies overestimated the damage done. Nor had the Allied leaders expected Germany to collapse under strategic bombing; they had viewed it as a softening-up process for an invasion and were content with the apparent results. 1 Nevertheless, it had fallen short of the aims set for it.
But all of this now changed, even though the strategic air forces were largely committed to supporting the invasion and the fight against the V-weapons. Although Bomber Command was in a difficult position, the Americans could now go anywhere in occupied Europe and had enough bombers to strike at the decisive targets: the enemy's oil production and transportation systems. Now the Americans were strong enough to take them on even while other tasks had priority.
On D-Day the Eighth Air Force reached its final complement of 40 heavy bomber groups (2,100 planes) and 15 escort fighter groups (nearly 1,000 fighters.) The equipment of the heavy bomber units did not change much during the rest of the war, save for the conversion of five B-24 groups to B-17s and the addition of still more planes to each group. But formations were altered to improve bombing accuracy and reduce losses to flak. The superiority of American fighters grew even more marked. The new P-51D, with a cut-down fuselage, bubble canopy, and heavier armament, was arriving. It eventually equipped 14 of the Eighth's fighter groups. Only the 56th Group retained later models of the P-47, with bigger drop-tanks. Fighter pilots got G-suits to cope with tight turns and pull-outs, and superior gyroscopic gunsights.