Leonardo da Vinci sketched glider-like aircraft with fixed wings inspired partly by bats.
Among Leonardo’s flight studies were designs for machines that relied on fixed wings and air moving over them, rather than flapping wings. His notes and drawings show an interest in bat wings because their membranes offered a useful model for a light but supported flying surface. These concepts belong to the early history of gliding rather than to powered aviation.
A glider is an aircraft that flies without an engine, using lift produced by its wings and moving air. Leonardo’s proposed machines were not tested aircraft, and historians do not treat them as proven gliders in the modern engineering sense. They are better understood as early theoretical studies of fixed-wing flight.
Leonardo also drew flapping-wing machines and a separate aerial-screw concept. Those ideas are often mixed together, but their flight mechanisms were different: fixed wings, flapping wings, and rotary lift are separate categories.