The chief of Boeing's commercial plane unit said overnight that orders might level off in 2008, but the company is hopeful US airlines are ready to start buying new aircraft, keeping it ahead of Airbus.

"I would think you would see some plateauing or some reduction in orders," Scott Carson said.

Mr Carson said he was hesitant to forecast any specifics but added that "one would think" US airlines may be at the point where they would start ordering more planes.

Boeing said this week that firm orders this year, now at 919 planes, could surpass the record of 1044 last year, when Boeing overtook EADS unit Airbus as the leading plane seller for the first time since 2000.

The aircraft sales boom in recent years has been driven by airlines in the Middle East and Asia, who have been busy expanding their operations.

European carriers just started this year making some big orders but major US customers, such as AMR Corp's American Airlines and UAL Corp's United Airlines, have not gotten around to any big purchases of wide-body jets.

Boeing this week trimmed its 2008 revenue forecast due to a six-month delay in deliveries of its 787 Dreamliner from next spring until late next year because of parts shortages and production problems.

Analysts have questioned whether the new schedule of delivering 109 Dreamliners by 2009 is achievable but Mr Carson said the company does not anticipate another delay and will know more about the plane once test flights begin early next year. The new schedule builds in a buffer to address issues that may arising during testing.

"We wouldn't put that number in there if it weren't achievable," Mr Carson said of the 109-plane target.

Boeing has received more than 700 orders for Dreamliners, its best launch ever. The program helped Boeing push past Airbus in sales despite the latter's A380 launch.