Don Mueang previously carried the BKK IATA code, which subsequently transferred to Suvarnabhumi and was an important hub of Asia and the hub of Thai Airways International prior to its closure. At its peak, it served most air traffic for the entire country, with 80 airlines operating 160,000 flights and handling over 38 million passengers and 700,000 tons of cargo in 2004. It was then the 14th busiest airport in the world and 2nd in Asia by passenger volume. Currently, Don Mueang is the main hub for Nok Air, Thai AirAsia and Thai Lion Air.