The Curtiss Model D was an early American biplane designed by Glenn Curtiss in 1911. It was notable for its innovative use of ailerons, which improved its maneuverability compared to earlier aircraft. The Model D was primarily used for training pilots and served as a foundation for future aircraft designs. This aircraft featured a 50-horsepower V-8 engine and had a wingspan of about 36 feet. The Model D played a significant role in the development of military aviation, as it was one of the first planes to be used by the U.S. Navy for training purposes.