The process of selecting a seat during the booking process is generally required, but some airlines may allow you to select that seat at the gate or during check-in. In most cases, airlines provide a seating chart when you book your flight, and you can select your seat then. Airline companies often charge extra for certain seats, like those with extra legroom or those located at the front. You will be assigned a seat by your airline if you do not select one while booking your flight. It may be possible for you to change your seat assignment at a later time for a fee.