The city shall have the exclusive right of the sale of all oil and gas and of all concessions and sales of whatever kind from the municipal airport; except, that if the city commission deems it advisable, the right for such sales may be transferred to other parties. Any person who dispenses aviation fuel at the municipal airport for private or commercial purposes must pay the city a minimum of two cents a gallon. This is not to include the filling of storage tanks by gasoline distributors. (Prior code §4A-7).