The great airline sale of 2009 may be ending. Air fares, which have shown steady drops throughout this year, are beginning to show signs of stabilizing. For travelers, that means waiting to book so prices can drop even more has probably run its course.

Fares in general are still much lower than they were last year. Travelocity reported that fall airfares fell 14 percent compared with fall 2008. But summer fares were down 18 percent.

Airlines are still running sales during good times and bad. But Tom Parsons, CEO of Bestfares.com, said they seem more widespread this year. "It's like every other day has an airfare sale from someone," he said.

Low-cost carriers have spread around the country to the point that they compete as much with one another as they do with big carriers like Delta and American.

Even Southwest isn't discounting as deeply as it used to. Parsons said airfares that once sold for $99 each way are now going for $149 each way.

None of this means the large airlines are out of trouble. They've been using sales to fill seats. But they're still waiting for revenue to get better, and business travel will need to pick up for that to happen. So far this year, business travelers, if they fly at all, have been increasingly flying coach and taking advantage of the same fare cuts that vacationers have been benefiting from.