Chapter 18.65 OVERLAY ZONING DISTRICTS This chapter is included in your selections. Sections: 18.65.010 General requirements – Overlay zoning districts. 18.65.020 “AP” Airport Overlay Zoning District. 18.65.030 “FP” Floodplain Overlay Zoning District. 18.65.040 “AO” Aesthetic Overlay Zoning District. 18.65.050 “P” Public Overlay Zoning District.