In 2024, the four largest U.S. airlines—Delta Air Lines, United Airlines, American Airlines, and Southwest Airlines—reported a combined operating profit of $14 billion. However, this profit was largely derived not from their core passenger flight operations, which collectively operated at a loss, but from partnerships with credit card issuers. These airlines generate substantial revenue through loyalty programs, including the sale of points and miles, which are funded primarily by credit card companies such as Delta's partnership with American Express. This business model positions the airlines more as operators of extensive credit card rewards schemes rather than traditional passenger transportation companies. Despite some debate, the consensus among industry observers is that the profitability of these airlines depends heavily on cash flows from loyalty and rewards programs rather than the direct business of flying passengers.