Leonardo da Vinci studied an ornithopter, a human-powered flying-machine concept designed to imitate the flapping motion of bird wings.
Leonardo filled notebooks with observations of birds, bats, and the mechanics of flight. His ornithopter ideas used wings that a pilot would move through mechanical linkages, treating flight as a problem of force, balance, and anatomy.
An ornithopter differs from a glider, which flies with fixed wings, and from a helicopter, which uses rotating blades. Leonardo’s studies also included gliding devices and the rotating aerial screw, so not every drawing of a flying machine belongs to the ornithopter category.
No evidence shows that Leonardo’s human-powered ornithopter achieved sustained flight. A human pilot cannot normally produce enough power with arm and leg muscles to flap wings of the necessary size. Leonardo’s lasting contribution was his systematic investigation of aerodynamics and biological flight, not a successful aircraft prototype.