Northwest Airlines on Monday announced plans to reduce the seats available out of Bismarck by 37 percent in August and a total of 24 percent in the fall, officials said.

The airline currently has 597 seats available on its six daily departures; on Aug. 6, the company will remove several larger planes and replace them with smaller ones, bringing capacity down to 375 seats, said Tim Thorsen, operations manager for the airport.

On Aug. 21, the capacity will go back up to 428 seats available, and should go up again to around 474 seats by September or October.

That's a total of about a 24 percent reduction, once it's all said and done, which means that some flights could be oversold, said Gary Ness, director of the state Aeronautics Commission.

"My concern is a lot of those seats have already been taken,"Ness said."That's not a good trade, especially when they're not adding flights."

The airline told administrators the reduction is part of a 4 percent nationwide reduction in operations due to a pilot shortage. Darrin Shannon, spokesperson for Northwest, said the reduction after Aug. 21 falls in line with the fall schedule, which typically has a lower demand.

"I understand that we are still operating the same frequency,"Shannon said, referring to the six daily NWAflights out of Bismarck. "If anything, frequency is more important to travelers."

Shannon said the company does not typically discuss individual markets, and could not comment further.

Airport boardings in Bismarck so far this year are down 0.4 percent; however, boardings were up 7 percent last year over 2005. Northwest's boardings are down by about 4 percent in Bismarck this year compared with last year. Ness said Bismarck is at about 64 percent of its daily capacity.

According to Ness, there have not been similar changes to the other major airports in the state.

Gov. John Hoeven said Northwest needs to maintain and, in fact, increase current airline seating capacity to support the current economic growth the city is seeing.

"Air travelers, especially business travelers, must have reliable, affordable service when they need it,"Hoeven said in a news release."Northwest needs to make every effort to maintain reasonable service and pricing for the benefit of North Dakota and the airline."

(Reach reporter Crystal R. Reid at 250-8261 or at crystal.reid@;bismarcktribune.com.)