American Airlines allows travelers to join the standby list if they miss a flight, depending on fare type and flight availability. Standby isn't guaranteed but can be a good option for same-day rebooking. Basic Economy tickets may not qualify, but higher-tier fares often do. Arrive early, speak to an agent, and ask to be added to the standby list. Being flexible with your schedule and destination can also increase your chances of catching the next available flight at no extra cost.