Any zoning ordinance adopted after October 1, 1949, by any county, shall not be effective, nor shall any zoning ordinance previously adopted remain effective six months after the effective date of this act unless:
(a) A provision is made in the ordinance for suitable areas in which airports may be located as conforming uses, or
(b) A finding is made by the governing body of the county that there is no site in the area zoned suitable for an airport.