An aircraft engine is a machine that propels an airplane by converting fuel into mechanical energy. There are two main types: jet engines and piston engines. Jet engines work by expelling high-speed exhaust gases, while piston engines use a series of cylinders and pistons to generate thrust. These engines are crucial for flight, providing the necessary power to lift the aircraft off the ground and maintain its speed and altitude. They are designed to be efficient and reliable, ensuring safe travel for passengers and cargo across long distances.