Rescheduling a flight at the last minute is generally possible but depends heavily on the airline's specific fare rules and seat availability. Most major carriers allow changes up to a few hours before departure, though "Basic Economy" tickets are often strictly non-changeable. In 2026, many airlines have maintained more flexible policies born from the pandemic era, though you will almost certainly have to pay the fare difference if the new flight is more expensive. If you are within 24 hours of departure, some airlines offer a "Same-Day Change" for a flat fee (often $75–$150), which is usually cheaper than a standard rebooking. However, if you miss your "check-in" window (usually 45–60 minutes before takeoff), the airline may mark you as a "no-show," at which point the ticket may lose all value. For the best results, use the airline’s mobile app for an immediate change, as wait times for phone support can be prohibitive during last-minute travel emergencies.