Cal. Rev. & Tax. Code § 6366
(a) There are exempted from the taxes imposed by this part the gross receipts from the sale in this state of, and the storage, use, or other consumption in this state of, the following:
(2)
(b) With respect to aircraft sold on or after January 1, 1997, it shall be presumed that a person is not engaged in business as a common carrier if the person’s yearly gross receipts from the use of the aircraft as a common carrier do not exceed 20 percent of the purchase cost of the aircraft to him or her, or fifty thousand dollars ($50,000), whichever is less. This presumption may be rebutted by contrary evidence satisfactory to the board showing that the person is engaged in business as a common carrier.
In no event shall “gross receipts” include compensation by the person or related parties for use of the aircraft as a common carrier.