Ohio Rev. Code § 4563.12: Permit required prior to substantial change or alteration.

Airport zoning regulations adopted under sections 4563.01 to 4563.21, inclusive, of the Revised Code, may require that a permit be obtained before any new structure or use may be constructed or established and before any existing structure or use may be substantially changed or substantially altered in an airport hazard area. No permit shall be granted that would allow the establishment or creation of an airport hazard, or permit a nonconforming structure to be made higher or a nonconforming object of natural growth to become higher or become a greater hazard to air navigation than it was when the applicable regulations were adopted or than it is when the application for a permit is made. If any nonconforming use is voluntarily discontinued for two years or more, any future use of the premises shall be in conformity with sections 4563.01 to 4563.21, inclusive, of the Revised Code.