It is recommended to select your seat at booking for the best fares and availability. The middle seat option allows the airline to seat passengers more conveniently, hence it costs less than the aisle or window seat. Passengers can also purchase the Works bundle, which includes a carry-on bag, checked bag, priority boarding, seat selection, flight flexibility, and itinerary change options. Frontier Airlines Seat Selection  offers different seating options when you book a flight. Passengers can choose to purchase a seat assignment or select a seat for free at check-in. You can choose from a standard seat or a stretch seat that offers additional legroom. The cost to select a seat varies depending on the type of seat selected and when the seat is purchased. The earlier you purchase the seat the cheaper it can be.