Dornier Do X is the largest, heaviest and most powerful flying boat produced by the Dornier company in 1929.

On February 20, 1929, the Do X test flight was complete, having 71 flights and had been airborne for 37 hours. Due to several lack of interest and a number of accidents, though not reported to be fatal, had prevented more than three models from being built. On July 12, 1929, it was launched for its first test flight, wherein it broke the world record for the number of people aboard an airplane. On Novermber 3, 1930, the Do X took off from from Friedrichshafen, Germany, commencing a transatlantic test flight. On August 27, 1931, the aircraft went of north to the United States, reaching New York, wherein it spent the next nine months for its scheduled overhaul.

The Do X had an all-duralumin hull, with wings made of a steel-reinforced duralumin framework covered in heavy linen fabric, covered with aluminum paint. Do X has a maximum speed of 211 km/h and a range of 1,700 km. It has a seating capacity of 66-100 passengers. Luxurious accommodation approached the standards of transatlantic airliners.

The Do X was featured in Michael Murrcock's alternate universe fiction, symbolizing power and style emblematic of the lost era of the 1930's. It was also featured in the 1934 movie, The Perils of Pauline, wherein it featured historic footage of the Do X's flight and in 1985 music video of the Alphaville pop group. Do X was also featured in an episode of Lupin III, Albatross: Wings of Death, wherein it depicted a twin-tail, having only five engines.