The primary commercial airport serving Beijing, Beijing Capital International Airport (PEK) is located about 20 miles northeast of downtown. In 2014 the airport – which serves as a hub for Air China, China Southern Airlines and Hainan Airlines – handled more than 86.1 million passengers, making it the busiest airport in Asia and the second busiest in the world. PEK has three runways and three passenger terminals: Terminal 1, Terminal 2 and Terminal 3. Shuttle buses connect all three terminals; a walkway also connects Terminals 1 and 2. Beijing Capital International Airport is connected to the city via the Beijing Subway. Several bus routes also connect the airport with Beijing and nearby cities. Other ground transportation options include taxis and limousines.