Major carriers operating between Dallas/Fort Worth International Airport (DFW) and Seattle-Tacoma International Airport (SEA) include American Airlines (frequent nonstop service), Alaska Airlines (strong Pacific Northwest network), Delta Air Lines, and United Airlines (one-stop options). In May, evaluate each carrier by flight frequency, seat comfort, baggage fees, and on-time performance. Alaska often offers competitive fares and strong regional connectivity into Washington state (Bellevue, Redmond), while American provides straightforward nonstop schedules from DFW. Compare loyalty program perks and seasonal promotions before booking to get the best value for your May trip.