Southwest Airlines Co. launched a 72-hour sale Tuesday to celebrate its 39th year in business, with fares starting at $39 each way.
For travel up to 450 miles, fares are $39 one-way. For travel between 451 and 1000 miles, fares are $79 each way. Fares are $119 each way for travel greater than that.
The fares are available through 11:59 p.m. Pacific time on Thursday for travel Sept. 8 through Nov. 17.
To book travel, visit www.southwest.com. Southwest fares aren't available on online travel sites like Expedia or Orbitz.
Eight to 10 months ago, short-window sales like Southwest's were unlikely. That has changed as airlines use quick booking to cater more to social media sites like Facebook and Twitter where impulse buys are more likely.