By Gary Stoller, USA TODAY
The weak economy may be bringing sky-high airfares down to earth.
With passenger demand for flights dropping, many airlines in recent weeks have instituted fare sales, and competitors have matched the lower prices.

CHART 1: Under-$300 fares popping up on popular routes
CHART 2: Airline schedule changes at 300 U.S. airports

The cheapest coach fares on many routes are half the price of a few months ago, and some for round-trip coast-to-coast flights are less than $300, based on a study by FareCompare.com for USA TODAY.

The price reductions — which follow a summer when airfares rose at a greater rate than any year in the past quarter century — are good news for holiday travelers who haven't yet bought their tickets, but maybe bad news for those with tickets in hand.

"We haven't seen consistent weekly sales of this magnitude in past falls and winters," says Rick Seaney, CEO of FareCompare.com.

Northwest (DAL) started the fare sales at the end of October, and at least seven other airlines have since had sales, Seaney says. Southwest Airlines (LUV) has had three fare sales, and last week extended its most recent one through Dec. 4.

To assess the fare sales, FareCompare.com on Sunday analyzed airfares for the 25 most-traveled domestic routes in the continental USA.

On more than half the routes, non-stop coach tickets were available for travel on Dec. 10 for less than $220 round trip.

Prices were higher for travel closer to Christmas but still relatively inexpensive. For travel on Dec. 24 and returning five days later, for example, non-stop tickets were available on most routes for less than $270 round trip.

"Those holiday prices would have been double eight to 12 weeks ago," Seaney says.

Ray Neidl, an industry analyst for Calyon Securities, says passenger demand is "down sharply" because of the weak economy.

Southwest spokeswoman Whitney Eichinger and JetBlue (JBLU) spokesman Bryan Baldwin confirm reduced demand.

"Booking activity during October for November did weaken, in line with what many retail stores have witnessed," Baldwin says.

It may not, however, be time for consumers to celebrate cheaper prices. Some of the cheapest fares for this holiday season are less expensive than a year ago, but each flight has many fares, and most are higher than they were during last year's holiday season, Seaney says.

Many carriers this year are charging for checked bags, a service that used to be free. A passenger with a $200 ticket may pay up to $80 more round trip for two checked bags — a 40% increase on what they paid a year ago.