A US aircraft manufacturer that has contributed to many space missions, including the Mercury project, building its capsule, and the Gemini project. It produced Saturn V third-stage rockets and converted one into the space station Skylab, launched on 14 May 1973. The corporation, whose headquarters are in St Louis, Missouri, merged with the Boeing Company in 1997.

On 30 August 1984, Charles Walker became the first astronaut to represent a private company when he flew on the shuttle Discovery in charge of McDonnell Douglas's electrophoresis operations in space (EOS) experiment, which investigated ways to process materials in microgravity.

The company was established in 1920 as the David Douglas Company. It became the Douglas Company in 1921, Douglas Aircraft Company in 1928, and McDonnell Douglas after a merger with the McDonnell aircraft company in 1967. It merged with the Boeing Company in 1997.