In the summer of 1943, the Eighth Air Force's fighter force consisted of P-47s which, lacking external drop tanks, could escort bombers no further than 230 miles from their bases in England -- far enough to reach Amsterdam or the coast of France, but not Paris, let alone Germany. Longer-ranged twin-engined P-38s were reserved for North Africa, the Mediterranean, and the Pacific, on the principle that the heavily-armed B-17 and B-24 bombers, flying in tight formation, could defend themselves.

The Germans, however, had other ideas. As the bombers began to strike at critical targets within the Reich, the Luftwaffe threw heavy fighter forces against them. Steady improvement in German tactics and equipment through the fall of 1943 was matched with steadily mounting bomber losses.

Recognizing the threat posed by German fighters, destruction of the fighter force was made a first-priority intermediate objective of the bombing -- not a strategic objective in itself but one which must be accomplished in order to allow freedom to pursue the ultimate strategic objectives. To accomplish this intermediate objective, attention was turned to the industry that produced Germany's fighters.

The Eighth Air Force leaders believed that it would be necessary to put 300 bombers over the target in order to punch through German fighter defenses without escorts and without excessive losses. Not until the Schweinfurt-Regensburg raids of 17 August 1943 were they in a position to put this to the test, and the results then -- with nearly twenty percent of attackers lost -- made it clear that any unescorted deep raids ran high risk, no matter how great the bomber strength.

As the summer of 1943 advanced the bombers continued to strike Germany as much as their strength permitted. The need for long-range fighter escorts had been recognized but progress was slow. By August the P-47s were fitted to carry 108-gallon centerline tanks which allowed them to escort to a radius of 375 miles. This put the very westernmost regions of Germany within escort reach, but not its industrial heart. The Luftwaffe fighters would wait until the escort had to turn back and then savage the naked bombers.

Because the importance of the targets was believed to justify the losses, however, the Eighth Air Force pressed on with its campaign of strategic bombing. But as the fall of 1943 wore on, the fighter arm of the Luftwaffe gained strength and expertise, and the toll grew heavier. Sometimes the bombers would manage to surprise the defenders through deceptive measures and get through relatively unscathed, but too often they had to bear the full weight of fighter attack, unescorted. The climax came on 14 October, when on their second visit to Schweinfurt the attackers lost 60 aircraft -- 19 percent of those dispatched and 26 percent of those which actually reached the target.

Finally, just after the Schweinfurt raid, a small force of P-38s was assembled to provide limited protection at longer ranges. With their two 75-gallon underwing tanks they could escort bombers to a radius of 520 miles, covering Germany's western half. Soon they were supplemented by P-51Bs, the first long-ranged, high-altitude version. The supply of drop tanks at last caught up with the need and by March 1944 all the fighters were able to carry two 108-gallon tanks under wing. With these the P-51s could cover all of Germany (850 miles radius), the P-38s could reach beyond Berlin and Munich (585 miles), and the P-47s could escort bombers to Frankfurt and Hamburg (475 miles).

In the spring of 1944 the key target was the German fighter force itself. Heavy attacks on aircraft plants in February had limited effects in themselves, but many Luftwaffe fighters were lost to the guns of the bombers and more to the escorting fighters, which now flew in relays to hunt the enemy rather than simply protecting the bombers. Heavy attacks were mounted for the first time against Berlin, stimulating intense air battles in which the Germans lost more fighters.

By this point the Germans, having taken the bombing threat too lightly earlier, were running short of pilots; more than half of Germany's fighter pilots were lost in the first three months of 1944-3 They were able to produce replacement fighters despite bombing, but pilot production was impeded by lack of fuel for training, resulting from limited oil resources available in Europe and heavy fuel demands for other urgent military needs. The Americans also suffered heavy losses but at least could supply replacements, which the Germans could not.