CHICAGO - U.S. airlines have slashed capacity, and recession-battered demand is showing signs of returning, but carriers like Southwest Airlines may scramble to fill planes this winter with big fare discounts, a fare expert said on Tuesday.

This is actually the best time to start shopping for air travel. In fact, there have been a bunch of fare sales filed last night, said Rick Seaney, chief executive of farecompare.com.

Southwest on Tuesday offered discounted fares on travel any day except Fridays and Sundays from Oct. 13 through Feb. 11.

It's a pretty big window, Seaney said. Southwest has been slowly extending their window of sales and flight schedules.

He said major carriers likely will match that sale soon. Seaney said fall and winter fares are down about 12 percent to 16 percent this year compared with last year.

The airline industry, weakened by volatile fuel prices and an economic recession in the last year, downsized in 2008 and 2009. Earlier this year, Delta Air Lines and AMR Corp's American Airlines announced capacity and staffing cuts.

Airlines say travel demand is slowly recovering. But some travel experts believe fare sales this fall and winter will reflect deep concern about upcoming ticket sales.

It's surprising to see sales at this time given the capacity cuts, said Terry Trippler at tripplersview.com, a travel opinion website. They've got to do what they can to get people to buy airline tickets.

It's rough on the industry right now, Trippler said. When will it snap back? It's hard telling.

He said the capacity cuts will ensure shorter lines at airports but larger crowds on planes. (Reporting by Kyle Peterson; Editing by Gary Hill)

American Airlines Winter