the second week of that month four full strength missions to Bremen, Marienburg, Münster and Schweinfurt had cost the Eighth Air Force 148 heavy bombers, fifty percent of its daily operational strength. The Americans then had to direct their attacks against targets within the range of fighter cover for the bombers. The RAF, having learned this lesson, were now executing their offensive by conducting night bombing operations on an increasingly large scale, with 1,000 bomber raids being assembled from 1942. Deep-penetration raids into Germany would be suspended until long range escorting fighters became available. The P-38 with 568 litre drop tanks were rushed back to operations over Europe after a year's absence to contend with the Jagdwaffe. Until the turn of the year the Luftwaffe would maintain air superiority over its homeland. The turn of the tide While the Battle of Britain was described as a "turning point" and caused losses that "could never be made good throughout the course of the war" the Luftwaffe was still able to combat bombing raids by the Allies. Until the development of Allied long-range fighters the Luftwaffe remained capable of inflicting serious losses by the day fighter and night fighter units (Nachtgeschwader), as well as the anti-aircraft guns under its command. The Luftwaffe employed twin-engined Ju 88 and Bf 110 Zerstörer, or bomber destroyer units to attack American formation with rockets and heavy cannon with considerable success. However, with the arrival of the long range P-51D these units suffered heavy losses. The disastrous Me 210, designed to replace the Bf 110, encountered design difficulties and was replaced with the Me 410 Hornisse, which was a development of the Me 210. The Me 410s were extremely vulnerable in hostile skies, and by 1944 were nothing more than cannon fodder for marauding Allied "day" fighters. The turn in the Luftwaffe's fortunes came during Big Week in which the U.S. Eighth Air Force flying from bases in Britain, and Fifteenth Air Force flying from bases in Southern Italy, carried out raids against the German aviation industry throughout Europe. The new commander of the US Eighth Air Force, Maj. Gen. Jimmy Doolittle's major influence on the European air war occurred early in 1944 when he changed the policy requiring escorting American fighters to remain with the bombers at all times. With his permission, initially performed with P-38s and P-47s with both previous types being steadily replaced with