| Cheap Flights: Austin to/from Denver or Chicago $98 r/t â Southwest [02/01/2020 @ 01:48 PM] Still available. Updated example dates. Southwest has round-trip flights from Austin (AUS) to Denver or Chicago (DEN, MDW) for $98, NONSTOP. $49 each-way. Most flights are between February to May. Mostly on weekdays. Origin/Destination reversible. Note: You may find additional savings if you book your Flight+Hotel together as a package on Southwest Vacations. Before you commit, always compare the prices of the individual Flights and Hotel with other hotel booking sites like Expedia or Tripadvisor. Read More Cheap Flights: Austin to/from Denver or Chicago $98 r/t â Southwest . | 