A glider is a type of aircraft designed to fly without an engine. It relies on rising air currents, known as thermals, to stay aloft. Gliders are typically made of lightweight materials, allowing them to glide smoothly through the air. Pilots control their flight using movable surfaces like ailerons and rudders. Gliders are often used in recreational flying and competitive sports, such as soaring. They can also serve educational purposes, helping students learn about aerodynamics and flight principles. The design of a glider emphasizes efficiency, enabling it to cover long distances with minimal energy expenditure.