MINNEAPOLIS — Boeing Co. has seen its orders peak and the number of planes in its backlog will probably decline going forward, the chief of its commercial airplanes division said on Wednesday.

"This year will certainly be a lower-orders year than the previous three, which were unbelievably strong," Boeing Commercial Airplanes President and Chief Executive Scott Carson told analysts at an aerospace and defense conference. "Everything that we see in the world today would suggest that next year will be down."

He said he didn't know how much orders would drop, but that they would be "down slightly from what we have seen this year," as the marketplace adjusts to the broader economic slowdown.

Boeing, the world's No. 2 commercial airplane maker after Europe's Airbus, has 3,734 aircraft on order. The airline world has been watching closely for word on delays caused by a two-month strike by factory workers that ended Nov. 2. Boeing said previously that the strike would push deliveries back by about that long, although it did not offer a firm date.

Spokesmen for both UPS Inc. and discount carrier AirTran Airways said they are expecting updated delivery schedules from Boeing in December.

Discount carrier AirTran Airways originally had two Boeing aircraft scheduled for delivery in December. Those aircraft will now come in February, spokesman Tad Hutcheson said. The carrier plans to sell those aircraft to a foreign airline.

A third plane has moved from January to April. And in mid-December AirTran expects an update for a fourth plane originally scheduled for April, Hutcheson said.

UPS Inc., the world's largest shipping carrier, has 27 new 767-300 freighters on order, with the first three expected in 2009.

American Airlines spokesman Andrew Backover said it is eager for new, more fuel-efficient 737s to replace MD-80s. But he said any delay now hurts less because fuel prices have come down.

On Friday, Chicago-based Boeing said its first 747-800s would be delayed by two to three quarters, pushing the freighter version into the third quarter of 2010 and the passenger version into the second quarter of 2011. It blamed the delay on design changes, limited engineering resources and the Machinists union strike.

Boeing's most closely watched plane is the 787. "We're still assessing where we are on that coming out of the strike," Carson said. Boeing had once hoped the plane, built for fuel efficiency with lightweight carbon composite parts, would make a test flight this year, but it has acknowledged that won't happen.

He said Boeing believes that even with an economic downturn, its orders are strong enough "that we have an excellent chance of building through the order cycle to the next upturn."

He said at the peak of cycles, its order backlog was about 40 percent U.S. carriers, but now is around 11 percent or 12 percent, with the rest of the orders spread around the world.

"We think this offers us maximum protection from any particular region's economic shock," he said.

Carson said one "emerging threat" is talk by smaller competitors of offering 100-seat planes. Northwest Airlines, before it was swallowed by Delta Air Lines Inc., often spoke of being on the lookout for a new 100-seat plane to replace its aging DC-9s.

"We continue to like the 130-ish size and up for our products," Carson said. "We continue to believe particularly with fuel and other constraints that that's what the sweet spot of the market will be, and we're watching very carefully what these emerging competitors are looking at to assure we don't give up any market space that's important to us."

Harry R. Weber, David Koenig and Daniel Lovering of the Associated Press contributed to this report.