Igor Sikorsky being used in most helicopters produced today. Igor Sikorsky was also on the board of directors for the Tolstoy Foundation Center in Valley Cottage, New York. Sikorsky was married to Olga Fyodorovna Simkovitch in the Russian Empire. They were divorced and Olga remained in Russia with their daughter, Tania, as Sikorsky departed after the October Revolution. In 1923, Sikorsky's sisters immigrated to the US, bringing six-year-old Tania with them. Sikorsky married Elisabeth Semion (1903–1995) in 1924, in New York. Sikorsky and Elisabeth had four sons; Sergei, Nikolai, Igor Jr. and George. Sikorsky died at his home in Easton, Connecticut, on
Igor Sikorsky a naturalized citizen of the United States. The Sikorsky Manufacturing Company moved to Stratford, Connecticut in 1929. It became a part of the United Aircraft and Transport Corporation (now United Technologies Corporation) in July of that year. The company manufactured flying boats, such as the S-42 "Clipper", used by Pan Am for transatlantic flights. Meanwhile, Sikorsky also continued his earlier work on vertical flight while living in Nichols, Connecticut. On February 14, 1929, he filed an application to patent a "direct lift" amphibian aircraft which used compressed air to power a direct lift "propeller" and two smaller propellers for thrust.