Cal. Rev. & Tax. Code § 10787

The license fee imposed by this part does not apply to any vehicle operated by the Civil Air Patrol, when the vehicle has been transferred to the Civil Air Patrol by the United States Government, or any agency thereof, if by federal regulation or directive the use of such vehicle is restricted to defined activities of the Civil Air Patrol, and if by federal regulation or directive the vehicle must be returned to the United States Government when no longer required or suited for use by the Civil Air Patrol.