Igor Ivanovich Sikorsky (Russian: И́горь Ива́нович Сико́рский, tr. Ígor' Ivánovich Sikórskiy; May 25, 1889 – October 26, 1972) was a Russian–American aviation pioneer in both helicopters and fixed-wing aircraft. His first success came with the S-2, the second aircraft of his design and construction. His fifth airplane, the S-5, won him national recognition as well as F.A.I. license number 64. His S-6-A received the highest award at the 1912 Moscow Aviation Exhibition, and in the fall of that year the aircraft won first prize for its young designer, builder and pilot in the military competition at Saint Petersburg.After immigrating to the United States in 1919, Sikorsky founded the Sikorsky Aircraft Corporation in 1923, and developed the first of Pan American Airways' ocean-crossing flying boats in the 1930s.

In 1939, Sikorsky designed and flew the Vought-Sikorsky VS-300, the first viable American helicopter, which pioneered the rotor configuration used by most helicopters today. Sikorsky modified the design into the Sikorsky R-4, which became the world's first mass-produced helicopter in 1942.