Twin-engine aircraft are airplanes that are powered by two engines, typically mounted on the wings or the fuselage. This design provides several advantages, including improved performance, increased safety, and better fuel efficiency compared to single-engine planes. If one engine fails, the aircraft can still operate safely with the remaining engine. These aircraft are commonly used for various purposes, including commercial flights, cargo transport, and military operations. Popular examples of twin-engine aircraft include the Boeing 737 and the Cessna 421. Their versatility makes them suitable for short-haul and long-haul flights, accommodating different passenger and cargo needs.