The majority of airlines give the option to choose the seats to the passengers either at the time of booking or subsequently via the "Manage Booking" or the check-in process. The available seat selection options and the costs incurred are usually determined by the fare type, route, and seat location. The standard seats can either be complimentary or offered for a small fee, whereas the preferred seats, those with extra legroom, and the ones with special features generally come with an extra charge.
A few basic or economy class tickets may have the seats assigned automatically at check-in. Travelers who are part of a group, who need assistance, or who are with young children usually get the airline's help according to its rules. The changing of seats is mostly permitted until the flight's departure, depending on availability.