Sikorsky designs and builds his first airplane, the S-1. While not initially successful, it marked his entry into fixed-wing aircraft construction and provided crucial learning experiences.

Sikorsky develops and improves upon his early designs with the S-2 and S-3 aircraft, achieving some success and furthering his understanding of aerodynamics and aircraft design.

These planes bring Sikorsky attention, particularly in the Russian military. He continues to learn how to improve aircraft designs with each new edition.

Sikorsky designs and builds the 'Le Grand' (also known as the 'Bolshoi Baltisky'), which is recognized as the world's first four-engine airplane. This aircraft demonstrated the potential of multi-engine designs for larger and more capable airplanes.

Based on the 'Le Grand', Sikorsky develops the 'Ilya Muromets', a larger and more refined four-engine aircraft that served as both a bomber and a passenger plane. This aircraft was a significant advancement in aviation and was put into service during World War I.

Sikorsky designed the S-16, a single-seat fighter aircraft. This marked his entry into the realm of fighter aircraft design and expanded his portfolio beyond multi-engine bombers and passenger planes.

Designed and built in the US, it was one of the first American transports. It was primarily used to carry supplies and personnel, but also served as a test bed for new technologies.