R101 was one of a pair of British rigid airships completed in 1929 as part of a British government programme to develop civil airships capable of service on long-distance routes within the British Empire. It was designed and built by an Air Ministry-appointed team and was effectively in competition with the government-funded but privately designed and built R100. When built it was the world's largest flying craft at 731 ft (223 m) in length, and it was not surpassed by another hydrogen-filled rigid airship until the Hindenburg flew seven years later — the U.S.