A biplane is a fixed-wing aircraft that has two fixed wings. The lower wing is often attached to the body of the aircraft and the top wing is raised above. Most early airplanes were biplanes because they have a stronger structure than a monoplane. When engineers found how to makes strong monoplanes, biplanes became rare because they produce more drag.
Famous biplanes include the Polikarpov Po-2, Sopwith Camel, Avro Tutor, Antonov An-2, Beechcraft Staggerwing, Boeing Stearman, Bristol Bulldog, Curtiss JN-4, de Havilland Tiger Moth, Fairey Swordfish, Hawker Hart, Pitts Special and the Wright Flyer. The Stearman is particularly associated with stunt flying with wing-walkers.