While in Paris, he met Blériot, Ferber, and others who were to become the great names in aviation. Despite advice to the contrary from them Sikorsky announced plans to build a helicopter. He bought a 25 h.p. Anzani engine and went home to Kiev to begin building a rotary-wing aircraft. His first two helicopter designs failed due to a lack of power and understanding of the rotary-wing art.

Sikorsky then began to work on fixed-wing aircraft. His first successful aircraft was the S-2, which was the second fixed-wing plane 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. In the fall of that year the aircraft won first prize in the military competition at Petrograd.

Sikorsky's success in 1912 led to a position as head of the aviation subsidiary of the Russian Baltic Railroad Car Works. Because of a mosquito-clogged carburettor and subsequent engine failure, he conceived the idea of a multi-engine airplane. This led to the construction of the four-engined "The Grand." The revolutionary aircraft featured such things as an enclosed cabin. a lavatory, upholstered chairs and an exterior catwalk atop the fuselage where passengers walk exposed to the air. His success led him to design an even bigger aircraft, called the Ilia Mourometz, after a legendary 10th Century Russian hero. More than 70 military versions of the Ilia Mourometz were built for use as bombers during World War 1.

The Revolution put an end to Sikorsky's career in Russian aviation. He emigrated to France where he was commissioned to build a bomber for Allied service. The aircraft was still on the drawing board when the Armistice was signed. Sikorsky was unable to find a position in France. This was the reason he emigrated to the United States in 1919.

Unable to find a position in aviation, Sikorsky resorted to teaching. He lectured in New York, mostly to fellow Russian émigrés. Finally, in 1923, a group of students and friends who knew of his reputation in pre-war Russia pooled their resources to launch his first American aviation venture, The Sikorsky Aero Engineering Corp. The first aircraft built was the S-29-A for America, a twin-engine, all-metal transport which proved a forerunner of the modern airliner. The company had its biggest success with the twin-engine S-38 amphibian, which Pan American Airways used to open new air routes to Central and South America. Later, as a subsidiary of United Aircraft Corporation Sikorsky's company produced the famous Flying Clippers that pioneered commercial air transportation across both the Atlantic and Pacific Oceans. The last Sikorsky flying boat, the S-44, held the Blue Ribbon for the fastest trans-Atlantic passage for years.

Sikorsky returned to the problem of rotary-wing aircraft. He had developed ideas for possible designs, some of which were patented. On September 14, 1939, Sikorsky took his VS-300 a few feet off the ground becoming the western hemisphere's first practical helicopter. Military contracts followed the success of the VS-300, and in 1943, large-scale manufacture of the R-4 made it the world's first production helicopter. The R-4 was followed by a succession of bigger and better machines and since then, the helicopter has become known for its ability to perform a many difficult missions in both peace and war.