Beijing has two of the world's largest airports. The Beijing Capital International Airport (IATA: PEK) located  northeast of the city center in Chaoyang District bordering Shunyi District, is the second busiest airport in the world after Atlanta's Hartsfield-Jackson International Airport.  Capital Airport's Terminal 3, built during the expansion for the 2008 Olympics, is one of the largest in the world. Capital Airport is the main hub for Air China and Hainan Airlines. The Airport Expressway and Second Airport Expressway, connect to Capital Airport from the northeast and east of the city center, respectively. Driving time from city center is about 40 minutes under normal traffic conditions. The Capital Airport Express line of Beijing Subway and the Capital Airport Bus serves the Capital Airport.