American Airlines has round-trip flights from Dallas (DFW) to Baltimore (BWI) for $139, NONSTOP. Flights August, September, and November. Departures on Tuesday, Wednesday, and Saturday. Extended weekends available. Origin/Destination reversible. No Thanksgiving dates.
A Carry-on bag and also a personal item is allowed for free on American. You can avoid paying for seat selection by accepting the randomly assigned seat at the gate.