Public Utilities Code § 21014
CHAPTER 1. General Provisions and Definitions
“Air navigation facility” means any facility, other than facilities owned or operated by the United States, used, or available or designed for use, in aid of air navigation, including any structures, mechanisms, lights, beacons, markers, communicating systems, or other facilities used or useful as an aid, or constituting an advantage or convenience, to the safe taking off, navigation, and landing of aircraft, or the safe and efficient operation or maintenance of an airport.