Boeing B-17 Flying Fortress Boeing B-17 Flying Fortress The Boeing B-17 Flying Fortress is a four-engined heavy bomber developed in the 1930s for the United States Army Air Corps (USAAC). Competing against Douglas and Martin for a contract to build 200 bombers, the Boeing entry (prototype Model 299/XB-17) outperformed both competitors and exceeded the air corps' performance specifications. Although Boeing lost the contract (to the Douglas B-18 Bolo) because the prototype crashed, the air corps ordered 13 more B-17s for further evaluation. From its introduction in 1938, the B-17 Flying Fortress evolved through numerous design advances, becoming the third-most produced bomber of all time,
Military history of the United Kingdom during World War II for the launching of Operation Overlord on 6 June 1944. Following Overlord, further direct support was provided to the troop, but Harris eventually succeeded in detaching his command from Eisenhower's control. The striking of German cities resumed. By the winter of 1944, the power of the British and American bomber forces had grown enormously. It was now routine for 1,000 bomber raids to be mounted by both American and British forces flying from the UK. American forces flying from Italy could also put several hundred aircraft above a target. Accuracy had improved, but it was still nowhere near good enough