One of aviation's greatest designers, Russian born Igor Sikorsky began work on helicopters as early as 1910. By 1940, Igor Sikorsky's successful VS-300 had become the model for all modern single-rotor helicopters. He also designed and built the first military helicopter, XR-4, which he delivered to Colonel Franklin Gregory of the U.S. Army.

The very first piloted helicopter was invented by Paul Cornu in 1907, however, this design was not successful. Another Frenchman, Etienne Oehmichen built and flew a helicopter 1 kilometer in 1924. An early practical helicopter that flew for a decent distance was the German Focke-Wulf Fw 61 invented by an unknown inventor.

Igor Sikorsky is considered to be the "father" of helicopters not because he invented the first. He is called that because he invented the first successful helicopter, upon which future designs were based.