California Code, Revenue and Taxation Code - RTC § 1154

(a) As used in this section, “air taxi” means aircraft used by an air carrier which does not utilize aircraft having a maximum passenger capacity of more than 60 seats or a maximum payload capacity of more than 18,000 pounds in air transportation and which holds a certificate of public convenience and necessity or other economic authority issued by the United States Department of Transportation, or its successor.

(b) Air taxis which are operated in scheduled air taxi operations are not subject to the provisions of Part 10 (commencing with Section 5301) of this division and shall be assessed in accordance with the allocation formula set forth in Section 1152.

(c) All other air taxis shall be assessed in the county where the aircraft is habitually situated in the same manner and at the same ratio as other personal property in the county subject to general property taxation. Such aircraft shall be taxed at the same rate and in the same manner as all other property on the unsecured roll.