Carriers servicing TUS→BKK itineraries typically involve U.S. majors (American Airlines, Delta Air Lines, United Airlines) with partner international carriers (Japan Airlines, ANA, Korean Air, EVA Air, Cathay Pacific). Choose based on preferred hub and loyalty program: American often routes via Los Angeles International Airport (LAX) or Dallas/Fort Worth (DFW) with Oneworld partners; United uses San Francisco International Airport (SFO) or Chicago O'Hare (ORD) with Star Alliance partners; Delta routes via Seattle (SEA) or Los Angeles with SkyTeam options. In May, consider aircraft type for the long-haul leg—look for lie-flat seats in business on premium aircraft if comfort is a priority.