| Cheap Flights: Austin to Portland, Oregon $156-$165 r/t [January-March] â American Airlines / United American Airlines and United have round-trip flights from Austin (AUS) to Portland, Oregon (PDX) for $156-$165 with a connection. Flights January to March. Departures on Monday, Tuesday, Wednesday, Thursday, and Saturday. Extended weekends available. Carry-on bag and seat selection is allowed for free on American. United has bag and seat fees. Click for more details and booking links Cheap Flights: Austin to Portland, Oregon $156-$165 r/t [January-March] â American Airlines / United . | 