Commercial operator – 14 CFR 1.1

Commercial operator means a person who, for compensation or hire, engages in the carriage by aircraft in air commerce of persons or property, other than as an air carrier or foreign air carrier or under the authority of Part 375 of this title. Where it is doubtful that an operation is for compensation or hire , the test applied is whether the carriage by air is merely incidental to the person’s other business or is, in itself, a major enterprise for profit.