Cal. Rev. & Tax. Code § 6366.1
(c) With respect to aircraft leased, or sold for the purpose of leasing, on or after January 1, 1997, it shall be presumed that the aircraft is not regularly used in the business of transporting for hire property or persons if the lessor’s yearly gross receipts from the lease of that aircraft to persons using the aircraft as common carriers of property or persons do not exceed 20 percent of the cost of the aircraft to the lessor, or fifty thousand dollars ($50,000), whichever is less. This presumption may be rebutted by contrary evidence satisfactory to the board showing that the aircraft is regularly used as a common carrier of property or persons.
In no event shall “gross receipts” include compensation by the lessor or related parties for use of the aircraft as a common carrier.