Inside German airspace, the Bf 109 G-6 fighters of 5 "Staffel"/JG 11, which had pioneered the fitment of the "Werfer-Granate 21" unguided air-to-air rocket weapon system to the Luftwaffe's single engine day fighter force the previous day, as well as the similarly armed rocket-launching twin-engined Bf 110 "Zerstörer" heavy fighters, including night fighters, joined the battle as more than 300 fighters from 24 bases opposed the raid. At 14:36 the force diverged from the morning's route at Worms, Germany, alerting the German defenders that the target was Schweinfurt. Losses among the 57 B-17s of the lead wing were so severe that many among its airmen considered the possibility that the wing might be annihilated before reaching the target. However, 15 miles from Schweinfurt, the opposing fighters, after shooting down 22 bombers, disengaged and landed to refuel and re-arm in order to attack the force on its way out. Five miles from Schweinfurt, German anti-aircraft guns began firing an effective flak barrage into the path of the bomber force.