Air China and China Eastern Airlines will each buy 15 planes. Shanghai Airlines will buy nine, and Xiamen Airlines will buy three. A deal for a further 18 planes for two other Chinese airlines remain under negotiation.

In a statement to the Hong Kong stock exchange, Air China, said it had agreed to purchase its 15 Boeing 787 aircraft from Boeing Company but was paying a discounted price for the rival to the Europe’s giant Airbus 380.

The statement said Boeing’s catalogue price for the 15 aircraft amounted to $2.16 billion but “after arm's length negotiation between the parties [the price to be paid] is lower than such catalog price”.

The 42 plane tranche of orders is reported to be worth around $5 billion.

In January, Boeing had announced “a preliminary agreement for the purchase of 60 Boeing 7E7 Dreamliners by Chinese airlines”. It said the agreement, to be finalised at a later date, was “valued at approximately US$7.2 billion, based on average list prices”.

At the time, Boeing described the 787 as “the perfect airplane to welcome the world to China during the 2008 Beijing Olympics”.

More prosaically, the Air China statement said it was expecting to take delivery of the Boeing Aircraft in stages from mid 2008 to end 2010 and that “they will principally serve long distance international destinations in North America, Europe and Australia. The Company expects the Boeing Aircraft will deliver more cost-efficient performance and provide more comfortable services to passengers.”