Cal. Pub. Util. Code § 21670.4

(a) As used in this section, “intercounty airport” means any airport bisected by a county line through its runways, runway protection zones, inner safety zones, inner turning zones, outer safety zones, or sideline safety zones, as defined by the department’s Airport Land Use Planning Handbook and referenced in the airport land use compatibility plan formulated under Section 21675.
(b) It is the purpose of this section to provide the opportunity to establish a separate airport land use commission so that an intercounty airport may be served by a single airport land use planning agency, rather than having to look separately to the airport land use commissions of the affected counties.
(c) In addition to the airport land use commissions created under Section 21670 or the alternatives established under Section 21670.1, for their respective counties, the boards of supervisors and city selection committees for the affected counties, by independent majority vote of each county’s two delegations, for any intercounty airport, may do either of the following:
1. (1) Establish a single separate airport land use commission for that airport. That commission shall consist of seven members to be selected as follows:
  1. (A) One representing the cities in each of the counties, appointed by that county’s city selection committee.
  2. (B) One representing each of the counties, appointed by the board of supervisors of each county.
  3. (C) One from each county having expertise in aviation, appointed by a selection committee comprised of the managers of all the public airports within that county.
  4. (D) One representing the general public, appointed by the other six members of the commission.
2. (2) In accordance with subdivision (a) or (b) of Section 21670.1, designate an existing appropriate entity as that airport’s land use commission.