Leonardo da Vinci sketched an ornithopter as a human-powered flying machine with birdlike flapping wings.
His surviving notebooks show several studies of birds, bats, wing structures, and mechanisms intended to transfer a pilot’s leg or arm power to wings. The designs reflect his belief that careful observation of birds could reveal principles of flight.
An ornithopter is not the same as a helicopter, airplane, or glider. It generates lift and thrust by flapping wings, whereas a helicopter uses rotating blades and a glider relies on aerodynamic lift without powered flapping. Leonardo’s designs were important conceptual studies, but they were not practical aircraft and were never proven to fly.