The Sikorsky Aircraft Corporation is an American aircraft manufacturer based in Stratford, Connecticut. Its parent company is United Technologies Corporation.

Sikorsky was founded in 1925 by aircraft engineer Igor Sikorsky, a Kiev-born American immigrant. The company, named "Sikorsky Manufacturing Company", began aircraft production in Roosevelt, New York that year. In 1929 the company moved to Stratford, Connecticut. It became a part of United Aircraft and Transport Corporation (now United Technologies Corporation) in July of that year.

In the United States, Igor Sikorsky originally concentrated on the development of multi-engined landplanes and then amphibious aircraft. In the late 1930s, sales declined and United Aircraft merged his division with Vought Aircraft. He took this opportunity to begin work on developing a practical helicopter. After first flying the VS-300 he developed the Sikorsky R-4, the first stable, single-rotor, fully controllable helicopter to enter large full-scale production (in 1942), upon which the majority of subsequent helicopters were based (though Sikorsky did not invent the helicopter itself).