The Boeing 720 is a jet airliner. It has two rows of seats, which means that it is a narrow-body airliner. It has four engines. The Boeing 720 was designed by Boeing in the 1950s. It was based on the Boeing 707, but the 720 is shorter and cannot fly as far. The 720 first took off in November 1959. Airlines began to use it in July 1960.