Southwest Airlines Co. is offering a sale geared toward leisure travelers who want to make short trips this spring.
The discount carrier said Tuesday it will sell tickets starting at $39 each way on some routes under 500 miles.
As usual, the airline didn't say how many seats it will offer at the sale prices, and Friday and Sunday flights aren't included. The sale ends Thursday and covers travel from March 15 through May 25.
Delta, American, United, Continental and US Airways matched the sale prices on routes where they compete with Southwest, said Tom Parsons, CEO of BestFares.com. Fellow discount carriers JetBlue and AirTran matched on some routes, he said.
Southwest has reported steadily rising traffic for several months — up 7.1 percent in January compared with a year earlier. The Dallas-based airline broke its own record for average occupancy in January. Still, 28 percent of seats were empty.
The sale shows that airlines are struggling to fill planes, especially during the relatively slow travel period between spring break and summer vacations.
"In order to fill up those last 20 percent of seats, Southwest still has to discount to get people off their couches and on to their computers booking tickets," said Rick Seaney, CEO of FareCompare.com.
Since the sale is mostly limited to short hops, the airline can still charge a reasonable price per mile, Parsons said.
"That's still money, and cost per mile is what they go by," Parsons said.
At $39 one way from Dallas to Houston, Southwest would get more than 16 cents per mile. In 2009, the airline's operating costs were a bit more than 10 cents per mile, so it can make a profit even at the sale prices if it can fill the planes.
But flights between San Francisco and Los Angeles would barely break even if every seat were taken at $39.