On 17 August 1942, Major Paul Tibbets led a formation of 12 United States Army Air Forces (USAAF) Boeing B-17E Flying Fortresses into a bomb-run over Rouen, France. Better known as the first pilot to drop an atomic bomb, on Hiroshima three years later, Tibbets was also the first pilot to fly a USAAF aircraft to bomb Nazi-occupied Europe. It would be the first of nearly 1,000 missions totalling over 600,000 sorties before the end of the war.
At the time of the Japanese attack on Pearl Harbor on 7 December 1941, the USAAF strategic bombing arm was small but growing. America’s geographical and political situation (both isolated and isolationist) precluded building an expensive strategic bombing force in the 1920s and 1930s. Although a solid core of its officers desired an independent long-range bombing arm, the Army Air Corps (as it was until June 1941) was firmly part of the US Army. They thought primarily in battlefield terms: investing in short-range tactical aircraft. Changes in naval policy in the early 1930s allowed the bomber supporters to develop a long-range heavy aircraft for maritime reconnaissance and, potentially, attacking enemy fleets. The result was the Boeing B-17. Only in 1938, with war looming in Europe, did US President Franklin D Roosevelt start a programme to expand America’s military. This led to the development of the Consolidated B-24 Liberator, an arguably more advanced type but with similar range and speed, although a smaller bomb load. By December 1941 only around 200 B-17s were in service, while the Liberator had just entered service that summer. Curiously, while the RAF progressed through ‘generations’ of bomber types, the USAAF would keep the same two basic bombers throughout the war