My client wants to book an economy ticket on Air France from Washington to India via Paris, but would like the option to upgrade at the airport if he needs it at the last moment. Would anyone know what is the minimum economy RBD that I have to book for airfrance for it to be upgrade-able. The cheapest availability is on V class. Will they be able to upgrade if I book them on V class? upgrade will be done using cash/credit card and not miles.