Winter Park Express provides winter weekend service from Denver to Winter Park Resort. Both trains stop at Denver's historic Union Station, where travelers can transfer to RTD's 16th Street Free MallRide or use light rail to tour the city. Airports Denver International Airport is the eleventh busiest airport in the world, and sixth in the U.S. In 2005, it handled 43.4 million passengers. In land area it is the largest airport in the United States, covering 53 sq. miles. Formerly Stapleton International Airport (replaced by Denver International Airport and closed in 1995) Formerly Lowry Air Force Base (flights stopped around 1965) Notes References External links The City and County of Denver