A biplane is a fixe-wing aircraft with two main wings. The first powered heavier-than-air aircraft, the Wright brothers' Wright Flyer, used a biplane design, as did most airplanes in the early years of aviation. While a biplane wing structure has a structural advantage, it produces more drag than a similar monoplane wing. Improved structural techniques and materials, as first pioneered by Hugo Junkers in 1915, and the need for greater speed, made the biplane configuration obsolete for most purposes by the late 1930s.