There are stories of people long ago who tried to imitate the birds by attaching wings to their arms. Of course, none could truly fly this way, but undoubtedly some were able to enjoy a controlled glide over a short distance. The first successful glider flight may have occurred in England about 900 years ago. A monk fastened wings to his hands and feet, jumped off a tower and glided about 600 feet (183 m) before making a rough landing that resulted in two broken legs. In 1498, an Italian learned how to glide with wings attached, but he also suffered a crash that broke a leg. Others down through the years tried to fly, but none gave any serious thought to the mechanics and aerodynamics involved.

The first to write an extensive analysis of the theory of human flight was Leonardo da Vinci. He sketched many ideas for human flight, nearly...