It was commissioned by the brewing magnate Ernest Guinness, and was the first British flying yacht built to the order of a private owner.

Soon afterwards it left England for Egypt, but stormy weather forced it to land off Cherbourg, and the crew, along with James and her fellow passengers, were rescued.

[7] Based on a 1927 design originally made for the requirements of specification R5/27 for a reconnaissance flying boat for the Royal Air Force,[8][6] it was built at the Supermarine works in 1929.

[7] The resulting modified design was a flying boat that weighed 10.1 long tons (10.3 t),[7] powered with three Armstrong Siddeley Jaguar engines.

[6] It included hull-mounted sponsons instead of the wing-mounted floats common on aircraft of this type, which caused it to resemble the German Dornier Do J;[6] a Supermarine employee afterwards wrote of Mitchell that "he had allowed himself to be lured by some of his bright boys into following other people's ideas.

"[3] Instead of a wooden biplane, Mitchell designed a monoplane made of metal,[3] with the wing held high above the fuselage on struts and stabilised laterally.

[3] When loaded with a full tanks of petrol, 600 pounds (270 kg) of baggage, and a minimum crew of three, the Air Yacht was designed to cover a distance of 2,000 miles (3,200 km) without re-fuelling.

[13] The three engines were replaced with three Armstrong Siddeley Panthers,[9] which increased the flying boat's maximum speed, but which still left it incapable of maintaining height when fully loaded with passengers, stores and fuel.

[6] In October 1932, it was seen by chance and then bought by a local wealthy American, Mrs June Jewett James, who knew little of the practicalities of flying an aircraft.

[2][13] James publicised her intention to use the flying boat to establish a regular trans-Atlantic service for passengers and cargo, once trials had been completed.

[6][16] On October 14, whilst in Cherbourg harbour, the crew and passengers had to call to be rescued and were landed onshore by tugboats, where they remained to await better flying conditions.

[11] The plane then flew on to Naples, where James obtained audiences with Pope Pius XI and the Italian dictator, Benito Mussolini.

[3] The flight to Egypt resumed on 25 January 1933, but an engine failed on take-off and later stalled, causing to the flying boat to ditch into the Gulf of Naples 7 miles (11 km) off Sorrento.