If the fighters were less of a menace, the flak was much more. Concentrations were dense, gunners good. Bomber losses mounted; in the summer months, the Eighth lost 922 heavies out of its operational force, most to flak, some to weather, and a few to fighters.

The bombing was working. By September, German fuel production was down to about one-quarter of its normal quantity. That throttling was felt deeply by the Luftwaffe, which was forced to park its fighters in vast arrays on the ground, out of fuel even for taxiing to a dispersal site. They were most appealing targets for any wandering fighter or bomber, and the Luftwaffe was losing them at the rate of 500 each week.

Paradoxically, German aircraft production never had been higher. The factories, many dispersed and some underground or in mountain caves, churned out complete fighters faster than they could be ferried away.

The heavies kept hammering at the oil targets, for even one-quarter of normal production was too much to allow to the Germans. The resiliency of the targets was impressive. Ploesti took multiple missions before its shutdown. The vast synthetic fuel plant at Merseburg-Leuna was another durable target. It was hit 22 times by USSTAF and twice by Bomber Command; they flew 6,550 sorties and dropped 18,328 tons of bombs on that single plant before they knocked it out for good.

The smarter Germans knew what was happening, and tried to make the point with Hitler or his staff. Albert Speer, the architect who became a production genius, said about the first raid against the synthetic fuel plants: "It meant the end of German armament production."