Travelers should always reconfirm their flights because flights can be rescheduled or canceled, sometimes at the last minute. In some cases, travelers who fail to reconfirm their flights within a certain time period risk losing their seat to other travelers.
According to Airtreks, it is not sufficient to rely on automated emails or mobile phone apps for alerts about flight schedule changes. The site recommends that travelers confirm their flights by calling the airline.
IndependentTraveler.com warns fliers that even with a confirmed reservation, a seat can legally be sold to another flier if the original ticketholder misses a reconfirmation deadline. Passengers who are bumped from a flight must have confirmed reservations in order to receive compensation.