Leonardo da Vinci studied ornithopters, winged aircraft designed to fly by flapping like birds or bats.
His notebooks contain numerous observations of birds, bats, wings, balance, and air currents. He designed several machines with large articulated wings and proposed that a pilot could operate them through pedals, levers, or body movement. These studies formed part of his broader investigation into whether human flight could imitate animal flight.
Leonardo correctly recognized that wing shape, weight, balance, and airflow mattered. However, human muscles could not supply enough power to lift a person with the mechanisms and materials available in his time. His ornithopters therefore remained designs and experiments rather than successful aircraft.
An ornithopter is not the same as a glider or an aeroplane. A glider relies on lift while moving forward, and an aeroplane uses powered propellers or jets with fixed wings. Ornithopters generate lift through repeated wing movement, a principle used by birds, bats, and many insects.