Airline rules, compared side by side

Airline policies are easiest to understand next to each other. These guides compare the big four U.S. airlines on one rule at a time, using the airlines' own published pages.

• Same-day flight change and standby rules by airline (2026)
  United, Delta, American and Southwest same-day change and standby rules side by side: what's free, what costs $75, who's excluded and the deadlines.
• The 24-hour flight cancellation rule, airline by airline (2026)
  How free 24-hour cancellation works at United, Delta, American and Southwest, what DOT requires, and the catches: 7-day minimum, Basic fares, partial cancels