You'll need to hurry.
For three days only, Southwest Airlines is selling one-way tickets for as little as $49. Sale fares booked by June 8 are valid for travel between August 22 and December 13
As USA Today pointed out, the $49 flights are largely valid on short, regional routes, like Washington, D.C. to Durham, North Carolina or Sacramento to Las Vegas. But for less than $100 round-trip, it might be worthwhile to plan a short, weekend-long trip in a neighboring state.
Southwest’s sale isn’t restricted to these ultra-cheap trips. Travelers can also find serious savings on more distant destinations and even a few international cities. Florida-based travelers, for example, can fly to Havana, Cuba for as little as $89 one-way, with the return leg costing $95 (a cool $184 round-trip, taxes included).
Flights originating in Boston include $59 one-way fares to Nashville and $58 flights to Atlanta, while flights departing from Los Angeles are on sale to Portland, Oregon; Tahoe, Nevada; and Denver, Colorado for $79 one-way.
Travelers should note that blackout dates apply, and seats are extremely limited. You’ll want to book well before the sale expires at 11:59 p.m., in the time zone of the originating city (that’s midnight PT for flights departing from California, for example, and midnight EST for flights departing from the New York area).
Travel dates and day-of-travel restrictions can also vary wildly depending on the city, so expect availability to fluctuate depending on your destination.