American Airlines has round-trip flights from Dallas (DFW) to Madrid (MAD) for $496-$506, NONSTOP. Flights October to March. 7-day minimum stay required. Flight may be marketed by Finnair, but operated by American.
Note: Carry-on bag is allowed for free on American Airlines. You can avoid paying for seat selection by accepting the randomly assigned seat at the gate.
Note: A slightly better deal than the Delta fare from a few days ago; the Delta deal required a stop. Keep in mind that previous deals with stops have been about -$80 cheaper than this.
Read More Nonstop Flights: Dallas to Madrid $496-$506 r/t – American