American Airlines and Southwest has round-trip flights from Dallas (DFW, DAL) to Seattle, New York, Los Angeles, Nashville, or Boston (SEA, LGA, LAX, BNA, BOS) for $105-$140, NONSTOP. Flights August to December. Weekends available. Origin/Destination reversible. No Christmas dates available.
This is a subset of the larger Domestic airfare sale that we mentioned earlier (link). Visit that post for a full list of every domestic fare being pushed by United, Southwest, and American right now.