Spirit has round-trip flights from Austin (AUS) to Baltimore (BWI) for $109-$117, NONSTOP. Flights May to June. Origin/Destination reversible.
Note: Spirit fares do not include a free carry-on bag. Only a small personal item, like a Jansport City Scout backpack is free. You can avoid paying for seat selection if you accept the randomly assigned seat prior to boarding.
Click for more details and booking links Nonstop Flights: Austin to/from Baltimore $109-$117 r/t – Spirit