| Nonstop Flights: Austin to/from Denver $97 r/t [May] â United United has round-trip flights from Austin (AUS) to Denver (DEN) for $97, NONSTOP. Flights in May. Departures on Tuesday, Wednesday, and Saturday. Extended weekends available. Origin/Destination reversible. Click for more details and booking links Nonstop Flights: Austin to/from Denver $97 r/t [May] â United . | 