Warning: Turbulence ahead

FASTEN your seat belts, fliers -- it could be a bumpy ride this fall and winter.

In many places, prices are increasing, seats are becoming more scarce and your favorite flight may have disappeared. The holidays are looking especially un-jolly.

The main culprit is a reduction in airline capacity. Pressured by bankruptcies and high fuel prices, many airlines are dropping routes, flying less often or using smaller planes for domestic service. Among them are American, Delta, Independence Air and Northwest.

International fliers may fare better. Although some nonstops to Asia have fallen to the budget ax, many U.S. airlines, including Continental and Delta, are adding foreign routes. The reason, experts say, is that these routes, freed from low-cost competition, can be more profitable.

Another break: United, which slashed service last fall and spring, doesn’t plan major cutbacks now because the airline has “already done that,” spokesman Jeff Green said.

Here are some tips for dealing with the turbulence:

Check for schedule changes. This is especially important for connecting flights.

Prepare to pay more. Since late summer, U.S. leisure fares have been 11% to 17% higher than last year at the same time, said Bob Harrell, president of New York-based Harrell Associates, which tracks the lowest published prices. You may get a price break if you travel now through early November or after Thanksgiving through Dec. 12, when demand is lower, said Barbara Messing, vice president of customer experience for Hotwire.com, an Internet travel seller.

Book holiday flights now. You already may be too late for popular destinations. “You’re finding prices are higher, and it’s more difficult to find space,” said Susan Tanzman, owner of Martin’s Travel & Tours in Los Angeles.

Round-trip airfares from Dec. 26 to Jan. 9 between LAX and Honolulu had topped $1,360 when Tanzman checked recently. She found that two out of three tour operators were sold out.

Get real about redeeming miles. Award seats have been getting scarcer. Capacity cutbacks are “just going to make a problem that was bad in the first place even worse,” said Tim Winship, editor and publisher of the online newsletter FrequentFlier.com. Book early, travel off-season and be willing to pony up extra miles for unrestricted awards, Winship advised.

Among U.S. airlines making changes:

American: The airline is canceling 15 round trips from Chicago’s O’Hare and Dallas-Fort Worth airports to a dozen domestic destinations and ending service between O’Hare and Nagoya, Japan, by the end of this month. Southern California service is not affected. U.S. cutbacks are taking place through Oct. 29, with the possibility of an extension.

Delta: The carrier is reducing domestic capacity by 15% to 20% and increasing international capacity 25%; route details have not been announced. Some domestic cuts will start in December; the rest of the changes will come next year.

Independence Air: Independence is ending service from Dulles Airport in suburban Washington, D.C., to LAX, San Diego, San Francisco, Seattle and five other airports, including New York’s JFK. The LAX route ended Oct. 2; look for other cuts by Dec. 1.

Northwest: The airline is reducing domestic capacity by 10%, including 38 fewer flights from its Minneapolis-St. Paul hub; reducing overall capacity by 8%; and suspending daily nonstops between New York’s JFK and Tokyo’s Narita airport. Southern California service is not affected. JFK-Tokyo service ended Oct. 2. Most other changes are to begin Oct. 31.