Sure, summer vacations season is underway. But that doesn't mean it's too early to start thinking of where you want to go this fall. To help you decide, Southwest Airlines has flash sale going on through 11:59 p.m. on June 6, with flights as low as $39. 

The sale includes flights between Aug. 20 and Dec. 18 with some blackout dates around Labor Day and Thanksgiving. You'll need to keep an open mind regarding departure and return dates in order to get the best deal as well. 

Here are some of the best flights hidden in the sale: 

Austin to San Diego for $79 Boston to Nashville for $79 Burbank, California to San Jose, California for $39  Charlotte, North Carolina to Baltimore for $49 Columbus, Ohio to Chicago for $49  Fort Lauderdale to Grand Cayman, Cayman Islands for $71 Houston to New Orleans for $49 Phoenix to Los Angeles for $49 Salt Lake City to Las Vegas for $49

Check out the sale for yourself on Southwest's flash sale page and start planning some long weekends. 

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