Boeing has announced deals to sell 10 billion dollars worth of planes to Air China – the country’s flagship carrier – and Hong Kong based Hainan Airlines.

Air China is buying five of Boeing’s newest, largest version of the 747 jumbo jet; with 450 seats it is a rival to the Airbus A380. It is a significant sale because orders for that Boeing aircraft have been slow.

China is the world’s fastest growing market and likely to buy more than 2,000 aircraft over the next five years.

As air travel becomes more popular among China’s increasingly wealthy population, Chinese airlines are keen to expand fleets to compete with regional players such as Singapore Airlines and Cathay Pacific.

China’s purchases of aircraft will help drive overall demand in Asia-Pacific, where average annual air traffic growth is expected to grow by 6.8 percent over the next 20 years, higher than the global pace, Boeing said. Asia-Pacific is likely to make up a third of global aircraft demand over the next 20 years.