Leonardo da Vinci studied the ornithopter, a flapping-wing aircraft modeled on bird-powered flight.
His notebooks contain many observations of birds, wings, muscles, and air currents. From these studies, he developed designs in which a human pilot would move wings through mechanical linkages, attempting to reproduce the flapping motion of a bird.
An ornithopter differs from a glider, which relies on fixed wings, and from a helicopter, which uses rotating blades. Leonardo’s surviving designs were exploratory and were not proven capable of carrying a person in sustained flight.
The studies nevertheless helped connect anatomy, mechanics, and aerodynamics in a systematic way. Leonardo recognized that human muscle power was probably insufficient for bird-sized flapping flight, and he investigated other arrangements of wings and controls in response.