Aviation Fuel The term aviation fuel means any liquid, other than gasoline or diesel fuel, that is suitable for use as a fuel in an aircraft. Nontaxable Uses The following are the uses of aviation fuel for which a credit or refund may be allowable to an ultimate purchaser. On a farm for farming purposes. Export. In foreign trade. Certain helicopter and fixed-wing air ambulance uses. Used other than as a fuel. In commercial aviation (other than foreign trade).