Jet Engines

Modern jet engines cut commercial aircraft fuel burn by up to 15 percent over predecessors

The primary driver of aircraft efficiency today is the engines. While advances in aerodynamics and materials do cut down on fuel burn as well, the engine is the main determinant as to how much fuel an aircraft burns, and older planes equipped with new engines tend to be more than competitive against a clean-sheet aircraft. During the start of the Jet Age, manufacturers were primarily focused on increasing power, with fuel efficiency being a second priority, but as technology has developed, this has changed.