Southwest Airlines offers a unique seat selection process, where passengers are not assigned a specific seat at the time of booking. Instead, they are assigned a boarding group and number, which determines the order in which they board the plane. Southwest Business Select Seating, Once on board, passengers can choose any available seat on a first-come, first-served basis. This system allows for more flexibility and freedom for passengers to select their preferred seat, and avoids the need to pay extra for seat assignments.