AirAsia has confirmed it has placed a $9.4 billion order for 100 more Airbus jets.
The deal for 64 revamped, fuel-efficient A320neo jets and 36 current-generation A320s comes on top of 375 similar planes already ordered by Asia's largest low-cost carrier.
"We have just bought 100 planes which makes a total of 475. To meet the amazing demand in Asia," AirAsia owner Tony Fernandes wrote on Twitter.
Britain, which co-operates in building Airbus planes together with France, Germany and Spain, said the deal would safeguard 9,000 British jobs including 1,500 at Airbus itself.
UK Prime Minister David Cameron said: "This is excellent news and a tremendous boost for the workforce and for UK manufacturing.”
"Today's announcement demonstrates the strength of the UK aerospace sector and the important role it plays in growing and rebalancing our economy.
"This Government will continue to back UK aerospace; cutting business taxes, investing in exports and working in partnership with the industry to ensure it is fully equipped to compete and thrive in the global race."
Tan Sri Dr Tony Fernandes, chief executive of AirAsia, said: "This order will meet our additional short and medium-term growth requirements as we see demand continue to rise across our network.
"The A320 has played a key role in our success, enabling us to offer our passengers the lowest fares possible and completely redefine short-haul travel in Asia."
Tom Williams, senior UK representative for Airbus, said: "This order comes as a huge boost for the teams in Broughton.
"We must not underestimate the importance of aerospace engineering and manufacturing in the UK which is highly skilled and high-value work, as demonstrated by the important role we play in providing a significant contribution to Airbus commercial airliners."
More than 8,800 A320 aircraft have been ordered and over 5,300 delivered to some 380 customers and operators worldwide.