Delta has round-trip flights from Austin (AUS) to Seattle (SEA) for $137, NONSTOP. Flights January to February. Departures on Tuesday, Wednesday, and Saturday. Extended weekends available.
Priceline has “Express Deals” for $127 on some of these dates. With “Express Deals” the airline and exact flight are hidden until after purchase and those purchases are final. It’s possible that the Express Deal may have a connection. There is no 24-hour free cancellation for “Express Deals”. The flight is guaranteed to be on a major airline. Be sure to select the deal with 0 to 1 stops and a layover less than 3-hours.
Click for more details and booking links Nonstop Flights: Austin to Seattle $127-$137 r/t [January-February] – Delta / Priceline Express