A "four-engine" aircraft is a type of airplane that is powered by four engines. These engines can be located on the wings or the fuselage, providing the aircraft with increased thrust and redundancy. This design allows for better performance, especially during takeoff and landing, and enhances safety in case one engine fails. Four-engine planes are commonly used for long-haul flights and cargo transport. Examples include the Boeing 747 and the Airbus A380. These aircraft can carry large numbers of passengers or heavy freight over long distances, making them essential for international travel and global trade.