The Boeing 737-400 is a narrow-body commercial airliner produced by Boeing Commercial Airplanes, a division of The Boeing Company. It is the fourth generation of the Boeing 737 family, following the 737-100/-200, 737-300, and 737-500. The 737-400 was designed to replace the 737-300 and compete with the Airbus A320 family.
The 737-400 was launched in 1985 and made its first flight in 1988. It entered service with Piedmont Airlines in 1989. The 737-400 was a commercial success, with over 480 aircraft produced. It was the best-selling variant of the 737 family until it was surpassed by the 737-800 in 2006.
