The Boeing 747-400 is a wide body, four-engine jet manufactured by Boeing, the American aerospace company. Its distinctive upper deck shape has earned it the nickname â??Jumbo Jetâ??. BA is the worldâ??s largest operator of the Boeing 747. The 747-400 is a proven performer with high reliability and incorporates major aerodynamic improvements over earlier 747 models, including the addition of winglets to reduce drag, new avionics, and a new flight deck. The 747 fits into today's infrastructure, serving more than 210 airports around the world and is also the world's fastest commercial jetliner. The 747-400's most noticeable aerodynamic improvement over previous 747s is the 6-foot (1.8-m) longer wing with a 6-foot-high winglet angled upward and slightly outward. This change reduces fuel burn and extends the aircraft's range. The winglet provides the effect of having an even greater wingspan without outgrowing the standard airport slot. The wingtip extension and winglet offer a fuel mileage improvement of about 3 percent, which during the life span of an airplane amounts to considerable savings.