An unpowered aircraft can also be referred to as a glider, sailplane, or soaring plane. These terms all describe aircraft that are designed to fly without an engine, relying instead on the natural forces of wind and gravity to stay aloft. Other synonyms for unpowered aircraft include hang glider, paraglider, kite, and balloon. Each of these aircraft has a unique design and method of flight, but all share the common feature of not having an onboard engine. Piloting an unpowered aircraft requires skill and experience, as the pilot must rely on instinct and the natural elements to navigate the skies.