China Southern Airlines said on Friday that its subsidiary Xiamen Airlines has agreed to buy 40 Boeing 737s as it expands internationally.

The bill for the jets, which will be delivered from 2016 to 2019, was significantly less than the list price of USD$ 3.36 billion in total because of concessions granted by Boeing, China Southern said in a statement.

The new aircraft will more than double Xiamen’s fleet by 2021 as the airline seeks to capitalise on the increasing wealth in China.