Detroit Metropolitan Wayne County Airport (KDTW) is a major international airport in the United States covering 4,850 acres in Romulus, Michigan, a suburb of Detroit. It is Michigan's busiest airport, and one of the largest airline hubs in the country. The airport is Delta Air Lines' second-largest hub by flight count. Detroit serves as the primary gateway to Asia for the Eastern United States for Delta and is also the third-busiest gateway to Europe for the airline. The airport has four main runways and two crosswind runways, two terminals, 129 in-service gates. Detroit Metropolitan Airport has maintenance facilities capable of servicing and repairing aircraft as large as the Boeing 747-400. In 2012 Detroit Metropolitan Wayne County Airport was the 16th-busiest airport in the United States and the 44th-busiest airport in the world.