A commercial airline’s purchase and subsequent importation of a jet engine into Hawaii for use as a spare part in the repair and maintenance of its jet aircraft fleet is not subject Hawaii use tax. The definition of “use” provides an exemption from use tax for material, parts, or tools imported or purchased by a person licensed under chapter 237 which are used for aircraft service and maintenance. Since the jet engine’s primary purpose is that of a spare part in furtherance of aircraft or aircraft engine upkeep, it constitutes a “part” and not a taxable “use.” (Letter Ruling No. 2010-01, Hawaii Department of Taxation, January 22, 2010)