Seat assignments are allowed by JetBlue Airlines on all flights. Advance seat selection for Blue Basic fares is only available for an additional fee. The passengers can purchase Even More Space seats directly with JetBlue by visiting its website or by calling the reservations department. JetBlue seat upgrade can be done for an Even More Space seat at the time of online check-in, at a kiosk or with a JetBlue Customer Service agent at the airport. Those who need additional seating room can also purchase an extra seat in the same fare option, which will also determine baggage allowance.