| Cheap Flights: Austin to/from Portland, Oregon $129 r/t [March-May] â United United has round-trip flights from Austin (AUS) to Portland, Oregon (PDX) for $129 with a connection. Flights March to May. Departures on Tuesday, Wednesday, and Saturday. Extended weekends available. Origin/Destination reversible. No change fees. Carry-on bag is allowed for free. Click for more details and booking links Cheap Flights: Austin to/from Portland, Oregon $129 r/t [March-May] â United . | 