747-400 United Airlines airplane model. Boeing launched the 747-400 in October 1985 and the first development aircraft first flew on April 29, 1988. US certification (with PW-4000s) was awarded in January 1989. The 747-400 externally resembles the -300, but it is a significantly improved aircraft. Changes include a new, two crew digital flightdeck with six large CRT displays, an increased span wing with winglets (the -400 was the first airliner to introduce winglets), new engines, recontoured wing/fuselage fairing, a new interior, lower basic but increased max takeoff weights, and greater range.