HKIA is an important contributor to Hong Kong's economy, with approximately 65,000 employees. Singapore Airlines and Ethiopian Airlines both utilise Hong Kong as a stopover point for their flights. It is a focus city for many airlines, including China Airlines and China Eastern Airlines. The airport is one of the hubs of Oneworld alliance, and also one of the Asia-Pacific cargo hubs for UPS Airlines. The airport is operated by the Airport Authority 24 hours a day and is the primary hub for Cathay Pacific (the flag carrier of Hong Kong), Greater Bay Airlines, Hong Kong Airlines, HK Express and Air Hong Kong (cargo carrier). It is also home to one of the world's largest passenger terminal buildings (the largest when opened in 1998). The airport is the world's busiest cargo gateway and one of the world's busiest passenger airports. Having been in commercial operation since 1998, Hong Kong International Airport is one of the largest trans-shipment centres, passenger hubs and gateways for destinations in Hong Kong, Greater China, Asia and the World. The airport is also referred to as Chek Lap Kok International Airport or Chek Lap Kok Airport, to distinguish it from its predecessor, the former Kai Tak International Airport. Hong Kong International Airport ( IATA: HKG, ICAO: VHHH) is Hong Kong's main airport, built on reclaimed land on the island of Chek Lap Kok, Hong Kong. Hiong 1gong 3 Get 5( or gok 5)zi 4 Gi 1cong 2