Leonardo da Vinci’s bird-inspired flying machine was an ornithopter.
An ornithopter is an aircraft designed to fly by flapping wings, rather than by using fixed wings or rotating rotors. Leonardo studied birds and bats extensively and produced several sketches for machines in which a human pilot would operate large wings through pedals, levers, and other mechanical linkages.
Leonardo’s designs were not powered aircraft in the modern sense. Human muscles cannot provide enough sustained power to lift a person with a practical flapping machine of the kind he drew. The sketches nevertheless show careful attention to wing structure, balance, airflow, and the different roles of lift and propulsion.
The term is broader than Leonardo’s work: modern ornithopters can be small experimental aircraft or robotic devices, and some use motors rather than human power. Leonardo also explored gliding and rotor-based ideas, so not every one of his flight drawings is an ornithopter. The defining feature is the intended flapping motion of the wings.