Southwest Airlines offers the best baggage policy among US carriers, with 2 free checked bags (up to 50 lbs each) on all fares. No other major US airline matches this. JetBlue includes a free carry-on on all fares, while Delta, United, and American charge $35-$45 for the first checked bag.

Both airlines offer comparable international networks. Delta is generally rated higher for customer service and on-time performance. United has a larger international route network, especially to Asia-Pacific. For baggage, both charge similar fees but Delta's SkyMiles program is often considered more valuable.

Among full-service US carriers, Southwest has no baggage fees (2 free bags). For budget carriers, Frontier and Spirit have the lowest base fares but charge $35-$65 for carry-ons. Internationally, Turkish Airlines, Emirates, and Qatar Airways include generous free baggage in economy.

Compare: 1) Total cost including baggage fees, 2) Route availability and connections, 3) Seat comfort and legroom, 4) Loyalty program value, 5) On-time performance, 6) Customer service ratings. Use Camli to search both airlines simultaneously and compare total trip costs.