Legacy airline schedules are essentially a dynamic, real-time bet on what travelers will do next year. For 2026, the simplest headline metric of which of America’s three largest airlines will operate the most flights seems like a fairly simple comparison, but it actually lies at the intersection of network strategy, overall fleet availability, labor dynamics, airport constraints, and demand trends that can change month to month. United Airlines, American Airlines, and Delta Air Lines are all capable of selling scale, but they choose to build it differently. American Airlines typically leans into frequency-heavy domestic connectivity through its hub system. Delta Air Lines more often chooses to protect yields and operational reliability, instead of favoring steadier schedules and stronger networks of banked hubs.