The 737-400 design was launched in 1985 to fill the gap between the 737-300 and the 757-200, and competed with the Airbus A320 and McDonnell Douglas MD-80.
O deseño do 737-400 foi lanzado en 1985 para encher o oco entre o 737-300 e o 757-200, e para competir co Airbus A320 e o McDonnell Douglas MD-80.