Southwest Airlines launches airfare sale with $40, $80 and $120 one-way fares

“You only turn 40 once,” Southwest Airlines says on its online sale page. Really? I feel as though Southwest has been ballyhooing birthday promotions forever -- not that I’m complaining. The airline Tuesday launched an autumn airfare sale with one-way fares of $40, $80 and $120 depending on how far you fly. But think fast because the offer is good only until Thursday. And be patient -- Southwest’s website may be slow to upload.

The deal: The Celebrating 40 Years With $40 Fares One-Way sale works this way: $40 for short flights (up to 450 miles), $80 for mid-range flights (451 to 1,250 miles) and $120 for long hauls (1,251 miles or more). Prices are one way and don’t include tax and fees. With this deal, sale fares apply to selected destinations every day except Fridays and Sundays. Also, the sale is online only.

Sample each-way fares from Los Angeles International Airport (LAX) include $40 to Las Vegas, Oakland, Phoenix, San Francisco; $80 to Salt Lake City, San Antonio, Denver, Portland, Ore.; and $120 toNew York, Boston, Baltimore. Sale fares also apply to departures fromBob Hope Airport (BUR), Ontario International Airport (ONT) andJohn Wayne Airport (SNA).

When: The offer is good for travel Aug. 23 through Nov. 16, but you have to purchase by 11:59 p.m. PDT Thursday. Blackout dates apply.

Tested: I had a hard time getting on to Southwest’s website Tuesday morning, probably because traffic volume was brisk. I found a sale fare of $120 each way, excluding tax and fees, fromLos Angeles to Boston, leaving Sept. 20 and returning Sept. 27. This sale could be a great way to snag a cheap seat for a fall colors trip or for college students returning to school.

Contact: Southwest Airlines