Frontier Airlines Phoenix Sky Harbor International Airport has flexible seating options. For travelers on a tight budget, standard seats are offered, while stretch seats offer more legroom for comfort. For a little cost, passengers can choose their seats when making their reservation, checking in, or at the airport. Employees at Frontier are on hand to help with special requests and seat upgrades. Traveling via PHX is a convenient and enjoyable experience thanks to the airline's seating offerings, which guarantee a balance between price and comfort.