Airline flights may be overbooked, and there is a slight chance that a seat will not be available on a flight for which a person has a confirmed reservation. If the flight is overbooked, no one will be denied a seat until airline personnel first ask for volunteers willing to give up their reservation in exchange for a payment of the airline’s choosing. If there are not enough volunteers, the airline will deny boarding to other persons in accordance with its particular boarding priority.
With few exceptions, persons denied boarding involuntarily are entitled to compensation. The complete rules for the payment of compensation and each airline’s boarding priorities are available at all US airport ticket counters and US boarding locations. Some airlines do not apply these consumer protections to travel from some foreign countries, although other consumer protections may be available. Check with your airline or your travel agent.