The first AAF unit in England to become operational was the 15th Bomb Squadron. On July 4, 1942, six of its crews accompanied six British crews of the RAF No. 226 Squadron on a low-level attack against enemy airfields in Holland. Two of the U.S.-built, but RAF-owned, Bostons flown by Americans were shot down.
On Aug. 17, 1942, the 97th Bomb Group made the first U.S. heavy bomber raid. Twelve B-17s, escorted by RAF Spitfires, attacked the Sotteville railroad yards at Rouen, France, while six other B-17s made a diversionary sweep along the French coast. All planes returned safely.
During the next several weeks, increasing numbers of B-17s attacked targets in France and Holland. On Sept. 6, Luftwaffe fighters came up in force and two B-17s were shot down, the first to be lost in combat over Europe. By Oct. 9, B-24s had joined the B-17s and all 112 AAF heavy bombers on a mission that date, three B-17s and one B-24 were shot down.
Following the Oct. 9 mission, the AAF was forced to slow its bombing campaign from England because of preparation for the invasion of North Africa. Four fighter and two heavy bomber groups were transferred to Africa, leaving one fighter group (formerly the three Eagle Squadrons) and six heavy bomber groups in England. Also, since American shipping to Africa had to be protected, the AAF was ordered to conduct an intensive campaign against Nazi sub bases on the west coast of France.