Who developed the first successful helicopter?

Igor Sikorsky is credited with developing the first successful helicopter, known as the VS-300, which made its first flight in 1939. Sikorsky's innovations and designs focused on a single main rotor with a tail rotor for stability, which became the foundational design for most helicopters that followed. His approach to rotorcraft design and understanding of rotor aerodynamics played a pivotal role in making helicopter flight practical and reliable.

In contrast, while other individuals like Albert Santos-Dumont and Henri Fabre contributed significantly to early aviation and experimented with rotorcraft, their designs did not achieve sustained and controlled flight in the way Sikorsky's models did. Arthur Young was instrumental in the development of rotor systems and the Bell Helicopter designs, but he was not responsible for the first successful helicopter flight. Sikorsky's contributions firmly established him as a pioneering figure in helicopter aviation history.