A jet airliner or jetliner is an airliner powered by jet engines (passenger jet aircraft). Airliners usually have two or four jet engines; three-engined designs were popular in the 1970s but are less common today.

The number of engines on a plane typically ranges from one to four, depending on the aircraft's size, intended range, and role. Most small general aviation planes, like the Cessna 172, utilize a single piston engine for cost-efficiency and simplicity. The vast majority of modern commercial jetliners, such as the Boeing 737 or Airbus A320, are twin-engine (two engines) because current technology allows them to fly long distances safely and efficiently on just two powerplants. Large, wide-body aircraft designed for massive payloads or extreme ranges, like the Boeing 747 or the Airbus A380, are equipped with four engines to provide the necessary thrust and redundancy. While three-engine planes (tri-jets) like the DC-10 were common in the late 20th century, they have mostly been phased out for more efficient twin-engine models. In 2026, the trend in aviation continues toward powerful, fuel-efficient twin-engine configurations even for the largest new aircraft like the Boeing 777X.