In 2024, the largest U.S. airlines—Delta, United, American, and Southwest—generated a combined operating profit of $14 billion, primarily driven by revenue from credit card partnerships and loyalty programs rather than passenger flight operations. Despite operating their passenger businesses at a loss, these airlines have built extensive frequent-flyer schemes that command valuations in the tens of billions of dollars, sometimes exceeding the equity value of the companies themselves. The loyalty programs, which include selling points and managing customer benefits, have become the core profit center, subsidizing losses from flying passengers. Airlines have increasingly structured loyalty status based on customer spending rather than flight frequency, allowing some customers to reach top tiers without flying. Delta noted that approximately 1% of U.S. GDP is spent through its co-branded credit cards, underscoring the scale of the credit card rewards business within the airline industry. These loyalty programs serve not only as a significant revenue source but also as important tools of corporate finance, binding together consumers, carriers, and credit card issuers.