biplane
An airplane with two wings, one above the other.
A biplane is an airplane with two sets of wings, one stacked above the other. If you look at a biplane from the front, you'll see an upper wing and a lower wing connected by struts (vertical support poles) and wires, creating a strong but lightweight frame.
Biplanes dominated aviation from the Wright Brothers' first flight in 1903 through the 1930s. The double-wing design gave these early aircraft extra lift and strength without making them too heavy, which mattered enormously when engines were still weak and materials weren't as advanced as they are today. Famous biplanes include the Sopwith Camel and the Curtiss JN-4 “Jenny” from the World War I era.
Modern planes are almost all monoplanes, meaning they have just one set of wings. As engines became more powerful and materials grew stronger, the single-wing design proved faster and more efficient. But you can still see biplanes at air shows performing stunts and aerobatics, where their maneuverability and nostalgic style make them crowd favorites. Some farmers also use small biplanes for crop dusting, since they can fly slowly and steadily at low altitudes.