Igor Sikorsky was a Russian-American aviation pioneer who is best known for his invention of the first successful helicopter. He was born in Kiev, Ukraine in 1889 and moved to the United States in 1919. He founded the Sikorsky Aircraft Corporation in 1923 and developed the first practical helicopter in 1939. He also designed the first four-engine passenger plane, the Sikorsky S-42, which was used by Pan American Airways in 1934. His innovations in aviation have had a lasting impact on the industry and he is remembered as one of the most influential figures in aviation history.