Fewer flights to hub airports in Dallas and at Chicago O'Hare are most likely, aviation analysts say. But popular destinations including Boston and New York LaGuardia also could be affected as American and its regional partner, American Eagle, shrink schedules amid soaring fuel costs.

"The price of fuel has gotten so high everyone, every location, is going to take a hit," said George Hamlin, managing director of ACA Associates, a Washington consulting firm.

American and American Eagle are the busiest carriers at RDU, offering 65 daily departures, or nearly 30 percent of the regional airport's flights. American has 19 daily departures, and Eagle has 46, according to RDU.

AMR Corp., the carriers' parent, announced Wednesday that American's domestic capacity -- measured in daily seats on flights -- would be cut in the fourth quarter. American and Eagle already had announced plans to stop service or downsize planes on four flights from RDU by Sept. 3.

The profitability of individual routes will determine which flights will be axed. Spokesman Andy Backover said a decision on the cuts had not been made.

With more than 5 million passengers boarding flights in 2007, RDU has market heft. That makes it unlikely that the most popular destinations would lose service completely.

Instead, routes with multiple daily flights at RDU could lose one or two. Those destinations include: Dallas (seven round trips), Chicago O'Hare (five), Boston (eight), LaGuardia (seven) and New York Kennedy (six).

"It's safe to say RDU won't be spared completely, but it's also safe to say RDU won't take a disproportionate share of cuts," said Michael Morstein, director of route planning and analysis at Intervistas Consulting in Washington.

Less popular routes with only two or three daily flights -- such as Columbus, Ohio; Jacksonville, Fla.; Louisville, Ky.; Kansas City, Mo.; and Hartford, Ct. -- could lose frequency or be stopped altogether.

American's daily round-trip flight to London from RDU isn't likely to be affected. The carrier plans to increase international service by 1 percent to 2 percent this year.