The AD Flying Boat was designed by the British Admiralty's Air Department to serve as a patrol aircraft that could operate in conjunction with Royal Navy warships. Intended for use during World War I, production of the aircraft was terminated as the end of the war came into sight, and the type saw little operational use. A number were re-purchased after the end of the War by Supermarine Aviation and rebuilt as civil Transports, becoming known as the Supermarine Channel.