SINGAPORE Airlines Ltd, Southeast Asia's biggest carrier, agreed to buy US$17 billion of aircraft from Boeing Co and Airbus SAS as economic growth across Asia spurs travel demand.

The airline agreed to order 30 more Airbus A350-900s and 30 Boeing 787-10x, SIA said in a statement yesterday. Planemakers usually give discounts from catalog prices.

In October, SIA ordered five Airbus A380 superjumbos and 20 A350-900s to expand its fleet and add fuel-efficient planes. Economic growth in Asia is encouraging more people to fly, prompting Indonesia's PT Lion Mentari Airlines and Malaysia-based AirAsia Bhd to order hundreds of aircraft to meet the travel boom.

"Today's aircraft orders are among the biggest in Singapore Airlines' history," said CEO Goh Choon Phong in the statement.

The agreement with Airbus comprises 30 firm orders of A350-900s for delivery from the 2016-17 financial year, plus options for 20 more, the statement said. The options may be converted into firm orders for larger A350-1000s.

The deal with Boeing covers 30 firm orders of B787-10Xs for delivery from the 2018-19 financial year, the statement said. It is conditional upon Boeing formally launching the B787-10X program.

The carrier is buying new aircraft after lower passenger and cargo fares pushed the company into a wider fourth-quarter operating loss. Goh is adding more planes, including Airbus A380s, and has upgraded business-class cabins as he faces increasing competition from Emirates and other airlines expanding in Southeast Asia.

Asia will be able to take in more aircraft as economic growth and a population of over 3 billion people will sustain travel demand, Tony Fernandes, head of AirAsia, the region's biggest low-fare carrier, said in March.

In March, Lion Air ordered 234 aircraft from Airbus - its second commitment to buy over 200 planes in two years.