The second of America's great four-engined heavy bombers of the Second World War, the Consolidated B-24 Liberator actually began development after the Army Air Corps approached the company to build B-17 Flying Fortresses. Unimpressed at the prospect, Consolidated proposed that they could design and produce their own bomber in the same time it would take them to establish production lines, and it would be better than a Flying Fortress. When their XB-24 prototype took to the air on 29th December 1939, it was a very different-looking aeroplane to the B-17 Flying Fortress, with its shoulder-mounted thin wings, deep, yet narrow fuselage and twin-boom tail, it had a maritime aircraft appearance about it. Following its eventual USAAF introduction in 1941, the B-24 Liberator was produced in vast quantities, serving in every theatre during the Second World War, and making a vital contribution to the Allied War effort.