Leonardo da Vinci studied an ornithopter, a human-powered flying machine based on flapping wings.
The word ornithopter comes from Greek roots meaning “bird wing.” Leonardo examined bird anatomy and flight and sketched machines in which a person would power large wings through pedals, levers, or other mechanical linkages.
His studies were part of a broader investigation of flight during the late fifteenth and early sixteenth centuries. Leonardo understood that birds combine wing motion, lift, balance, and air resistance, although the human muscles available to a pilot could not provide enough power for sustained flapping flight.
An ornithopter is not the same as Leonardo’s aerial-screw concept. The ornithopter depends on flapping wings, whereas the aerial screw proposed rotary motion. Neither concept became a practical aircraft in Leonardo’s lifetime, but both influenced later discussions of aviation.