Southwest Airlines offers 1-way fares nationwide with prices starting at $59. (Click on "Southwest Airlines" in the top line to see this sale.) That's the lowest price we could find for select routes by $169. This price is valid on flights departing from Austin, TX, (AUS) to Dallas, TX, (DAL) on April 21. Book this travel deal by April 6 for travel from March 31 through June 3. Click here to see more routes.