The Boeing B-17 Flying Fortress is an American four-engine heavy bomber aircraft developed for the U.S. Army Air Corps (USAAC). Competing against Douglas and Martin for a contract to build 200 planes, the airplane outperformed both the other entries and the Air Corps' expectations. Although losing the contract due to an accident, the Air Corps was so in favor of the B-17 that they ordered 13 B-17s regardless. Evolving through numerous design stages, from B-17A to G, the Flying Fortress is considered the first truly mass-produced large aircraft. From its pre-war inception, the USAAC touted the aircraft as a strategic weapon; it was a high-flying, long-ranging potent bomber capable of defending itself. With the ability to return home despite extensive battle damage, its durability, especially in belly-landings and ditchings, quickly took on mythical proportions.
The B-17 was primarily involved in the daylight precision strategic bombing campaign of World War II against German industrial targets. The United States Eighth Air Force based in England and the Fifteenth Air Force based in Italy complemented the RAF Bomber Command's night-time area bombing in Operation Pointblank, which helped secure air superiority over the cities, factories and battlefields of Western Europe in preparation for Operation Overlord. The B-17 also participated, to a lesser extent, in the War in the Pacific.