Boeing became the first commercial airframe manufacturer to use the moving line concept to build jetliners when first the 717, and then the 737, production lines were transformed into a moving line. The moving line helps reduce the time to assemble the airplane and also cuts inventory and production costs. Once the wings and landing gear are installed, the 737 is pulled to the Moving Line. As each 737 moves along the assembly line at a rate of 2 inches (5 centimeters) per minute, the tail fin and horizontal stabilizer are added and all parts are installed in the flight deck and passenger cabin.