Nonpowered heavier-than-air craft capable of sustained flight. Early experimenters in glider flight included George Cayley, who built the first man-carrying glider in 1853, and Otto Lilienthal (1848–1896), who introduced tail stabilizers on his first practical man-carrying craft in 1891. Improvements by Octave Chanute (1832–1910) in 1896 and by Wilbur and Orville Wright in 1902 perfected the control needed for developing the Wrights' powered airplane in 1903. The slender-winged glider was launched by being towed behind an airplane or a car. Gliders were used in World War II to carry troops. Today they are mainly used for recreation; the sailplane type is built for soaring on the lift from thermals. See alsohang gliding.