Washington Dulles International Airport (IAD) is located in Virginia's Loudoun and Fairfax counties, about 25 miles west of downtown Washington, D.C. One of three airports serving the Washington metropolitan area, Dulles is a United Airlines hub and handles nearly all of the region’s international passenger traffic. Named after John Foster Dulles, President Eisenhower’s Secretary of State, it opened in 1962. The main terminal, designed by Eero Saarinen, is an icon of modernist architecture, though its layout requires passengers to take the AeroTrain or a “mobile lounge” people mover to their gates after checking in.