Singapore: Boeing is facing growing anger from its biggest customers for delays in its new 787 Dreamliner, but still unveiled more than $6 billion in orders for other planes at the Singapore Airshow.

Indonesian carrier Lion Air ordered an additional 56 737-900ER planes, worth $4.4 billion at list prices, in the largest confirmed order for the planemaker, which is trying to manage fallout from the repeated Dreamliner delays.

International Lease Finance Corp (ILFC), the world's top plane leasing firm, said it will seek large compensation from Boeing for the delays, which will push its Dreamliner deliveries back by between 9-12 months to late 2010 or early 2011.

ILFC is the biggest buyer of Boeing's 787, with 74 of the fuel-efficient jets on order, but the planemaker announced last month that the plane has hit a second delay, pushing first deliveries out until early 2009.

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"We've put Boeing on notice that there will be some very serious talks," Steven Udvar-Hazy, chief executive of ILFC, said. Asked if ILFC will seek compensation, he said: "Definitely, on a large scale."

Airlines including Japan's All Nippon Airways - due to be the first to take delivery of the aircraft - Australia's Qantas and Air India have said they will consider seeking compensation, which could cost Boeing billions of dollars.

Airlines have so far ordered 857 of the planes, worth $140 billion at list prices.

"It's not only the impact on us, it's the impact on our leasee - the airlines," Hazy said, adding that 15-20 of ILFC's 787 orders are expected to be affected by the delay.