How big is an airplanes engine?

The size of an airplane engine varies significantly depending on the type and model of the aircraft. For commercial jet engines, they can range from about 5 to 12 feet in diameter and can be over 20 feet long. Smaller aircraft engines, like those in general aviation planes, are typically much smaller, often measuring around 2 to 4 feet in diameter. Overall, the engine size is designed to meet the specific thrust and efficiency requirements of the aircraft it powers.