American Airlines and British Airways have round-trip flights from Dallas (DFW) to Barcelona, Madrid, Cork Ireland, and Lisbon (BCN, MAD, ORK, LIS) for $497-$537. 7-day minimum stay required.
Barcelona: Flights August, September, February, March, and April. Nonstop.
Madrid: Flights June to April. Nonstop.
Cork: Flights July to April. With a connection.
Lisbon: Flights August to April. With a connection.