Birds inspired Leonardo da Vinci’s ornithopter designs. An ornithopter is a machine intended to fly by flapping wings, imitating the movement of a bird or another winged animal.
Leonardo studied bird anatomy, wing structure, and the mechanics of flight in numerous notebooks. His designs included wings operated by human muscular effort, with the pilot moving pedals, levers, or other controls. He recognized that flight depended on more than simply copying a bird’s outline, so he examined balance, air resistance, and wing movement as well.
No Leonardo ornithopter is known to have flown. Human muscle power is not sufficient for a large flapping aircraft of the type he sketched, and the designs lacked a practical lightweight power source. Even so, his investigations helped establish a systematic approach to studying flight and influenced later attempts to build flapping-wing machines.