Aircraft engine

An aircraft engine produces thrust directly or shaft power for a propeller or rotor. Its design balances power, weight, fuel use, reliability, and operating altitude.

Jet engine: An engine that produces thrust by accelerating a stream of gas rearward. Jet engines generate thrust directly from exhaust rather than driving an external propeller.
Thrust: A force produced by accelerating mass in the direction opposite the force. Thrust is the direct output of jet engines and the propulsive effect of propellers.
Commercial aviation: The operation of aircraft to transport passengers or cargo for hire. Airliners commonly use turbofan engines chosen for long-range speed and efficiency.
Turbojet: A gas turbine engine that produces thrust mainly by accelerating its core exhaust. It contrasts with high-bypass turbofans, which accelerate much more air at lower speed.
Jet Age: The period when jet-powered aircraft transformed commercial and military aviation after the Second World War. Turbine engines enabled faster, higher-flying airliners and expanded long-distance travel.
Turboprop: A gas turbine engine that drives a propeller through a reduction gearbox. Most of its thrust comes from the propeller, with a smaller contribution from exhaust.
Shaft power: Mechanical power transmitted by a rotating shaft. Turboprops and piston engines deliver useful power through a rotating shaft.
General aviation: Civil aviation other than scheduled airline and military operations. Many small general-aviation aircraft use piston engines and propellers.
Ramjet: An air-breathing jet engine that compresses incoming air through forward motion, without a rotating compressor. A ramjet cannot produce static thrust and operates only at high forward speed.
Aircraft noise: Sound produced by aircraft, especially during takeoff, landing, and low-altitude flight. Engine and exhaust noise prompted quieter designs and restrictions around airports.

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