A "twin-engine" refers to a type of aircraft that is powered by two engines. This design can enhance performance, reliability, and safety, as the aircraft can still operate if one engine fails. Twin-engine planes are commonly used for commercial flights, cargo transport, and military missions. In aviation, twin-engine aircraft can vary in size and purpose, ranging from small private planes to large commercial jets like the Boeing 737. They are often favored for their ability to cover long distances while maintaining fuel efficiency and providing a smoother ride compared to single-engine planes.