Southwest Airlines will begin service between Ronald Reagan Washington National Airport (DCA) and Lambert-St. Louis International Airport (STL) with two daily nonstop roundtrip flights starting Sept. 30, 2012. To celebrate the new route, the carrier also announced a fare sale of $139 one-way between the two nonstop markets when purchased only at southwest.com or swabiz.com through Aug. 6, 2012, at 11:59 p.m. PT.

This fare is available for travel on Tuesdays, Wednesdays, and Saturdays when travel takes place between Oct. 2, 2012, and Nov. 14, 2012 (blackout date of Oct. 6, 2012, applies). Southwest Airlines began service to DCA on July 8, 2012, with daily nonstop roundtrip service to Austin. The new STL service is made possible by Southwest's recent purchase of four inside-perimeter slots at DCA.

Southwest Airlines also has been expanding its presence in St. Louis, a market the carrier has served for more than 25 years. Southwest is the largest carrier at STL with DCA being its 34th nonstop destination out of the market. Southwest recently added flights between STL and markets such as Newark, Nashville, New Orleans, Raleigh-Durham, Milwaukee, and Seattle. The carrier also will begin service between St. Louis and both New York LaGuardia and San Antonio beginning Aug. 12, 2012.