Hong Kong International Airport is the main airport in Hong Kong. It is located on the island of Chek Lap Kok, which largely comprises land reclaimed for the construction of the airport itself. The airport is also colloquially known as Chek Lap Kok Airport (赤鱲角機場), to distinguish it from its predecessor, the closed Kai Tak Airport.The airport has been in commercial operation since 1998, replacing the Kai Tak Airport. It is an important regional trans-shipment centre, passenger hub and gateway for destinations in Mainland China (with 45 destinations) and the rest of Asia. The airport is the world's busiest cargo gateway and one of the world's busiest passenger airports. It is also home to one of the world's largest passenger terminal buildings (the largest when opened in 1998).The airport is operated by the Airport Authority Hong Kong 24 hours a day and is the primary hub for Cathay Pacific (the flag carrier of Hong Kong), Cathay Dragon, Hong Kong Airlines, Hong Kong Express Airways and Air Hong Kong (cargo carrier). The airport is one of the hubs of Oneworld alliance, and it is also one of the Asia-Pacific cargo hubs for UPS Airlines. It is a focus city for many airlines, including China Airlines and China Eastern Airlines. Singapore Airlines, Ethiopian Airlines and Air India utilize Hong Kong as a stopover point for their flights.