Delta Air Lines is a global passenger airline operating a hub-and-spoke network across the U.S. and internationally, with core hubs in Atlanta, Detroit, Minneapolis-St. Paul, and Salt Lake City, plus coastal hubs in Boston, Los Angeles, New York, and Seattle. Delta sells seats ranging from economy (main cabin) to premium products including Delta One (long-haul business class), Delta Premium Select, First Class, and Delta Comfort+. Delta targets higher-income travelers and is actively shifting its revenue mix toward premium cabins, which carry materially higher margins than main cabin. Delta also generates significant revenue outside of flying: its co-brand relationship with American Express — where Delta sells SkyMiles to Amex for use in co-branded credit cards — reached $8.2B in FY25 and is the company's single largest external revenue relationship. Delta TechOps provides engine, airframe, and component maintenance to third-party airlines. Delta's regional feeder network, Delta Connection, is operated by Endeavor Air (wholly owned), Republic Airways, and SkyWest. Internationally, Delta participates in four antitrust-immunized joint ventures covering transatlantic, transpacific, U.S.-Latin America, and U.S.-Mexico routes, enabling coordinated pricing and scheduling. Delta owns the Trainer oil refinery through its Monroe Energy subsidiary, partially hedging jet fuel refining margins. Delta's growth strategy centers on expanding premium cabin capacity via new wide-body aircraft deliveries, growing American Express remuneration toward $10B, and scaling MRO third-party revenues.