Leonardo da Vinci designed ornithopter concepts with wings intended to be operated by a human pilot.
An ornithopter is an aircraft that flies by flapping wings, imitating the motion of birds or bats. Leonardo studied bird anatomy, wing movement, air resistance, and the mechanics needed to transfer human effort to large wings. His notebooks contain several proposals, including designs in which the pilot’s arms and legs would operate linked mechanisms.
The major engineering obstacle was power. Human muscles cannot supply enough energy for a machine of the required size to flap wings and lift a person. Leonardo eventually recognized that gliding and the action of air currents offered more realistic possibilities than pure human-powered flapping flight.
An ornithopter is not the same as a glider. A glider depends on aerodynamic lift with fixed or largely fixed wings, while an ornithopter generates lift through repeated wing motion. Leonardo’s ornithopter drawings are therefore important as studies in biomechanics and flight, even though none is known to have flown.