Detroit Metropolitan Airport (airport code DTW) serves more than 32 million passengers a year. It has two terminals, the North Terminal and the McNamara Terminal. The airport is 20 miles (32 km) southwest of downtown Detroit. Although there is no rail service from the airport, there are plenty of rental cars, taxis, shuttles and buses available to points throughout the region including the University of Michigan in Ann Arbor, only 25 miles (43 km) away. The airport operates continuous, free shuttle service connecting the two terminals. As a major hub for Delta Air Lines and the SkyTeam Alliance, DTW serves as the primary U.S. gateway for Delta flights to Asia. Together, 11 airlines provide more than 600 flights per day from DTW to destinations on four continents. The 400-room, AAA four-diamond Westin Detroit Metro Airport hotel is connected directly to the airport at the McNamara Terminal and, as part of a pilot program with TSA, allow registered guests to pass through security to enjoy the terminal's more than 100 shops, restaurants and services.