620 ILCS 50/53
The Commission shall within six months following its organization, designate the locality, the class and type of the airports that shall come under the provisions of this Act.
The airport or airports to be so designated shall facilitate travel by aircraft between the principal cities and trading points in each county with each other, and also with the principal cities and trading points in other counties. The Commission shall indicate the locality of each Airport so selected, by marking them upon some map which shows among other features, the public roads, railroads, mains, pipes, conduits, wires, cables, poles and other facilities and structures of public service corporations or municipal or quasi-municipal corporations, incorporated areas, existing airports, and shall indicate the class and type of airport to be so located.
In designating the locality, the class and type of airports, the Commission shall have due regard for the following factors: the present and future needs of local interstate and intrastate private flying; the existing and contemplated airport facilities, including those owned or controlled or to be owned or controlled by the Federal Government; the then current State airport plan and State airways system; and the avoidance of unnecessary or unreasonable interference or conflict, on the part of airports, airport plans and airport facilities, with existing important or essential facilities or buildings devoted to the public use. Within ten days after the adoption thereof, certified copies of such maps shall be filed with the Department, in duplicate.
The Department shall examine the map with the airports located thereon, and if the Department finds the airports to be properly located and designated as to class and type, one of the maps shall be returned within thirty days to the county airport commission, with the approval of the Department endorsed thereon. If the Department finds that the airports selected and designated by the Commission do not adequately or efficiently facilitate travel by aircraft between the principal cities and trading points in each county with each other, and also with the principal cities and trading points in other counties, or the type or class of airport designated by the County Airport Commission is deemed to be improperly specified, the Department shall make such changes as will, in its judgment, best serve to facilitate such travel and shall within thirty days after the receipt thereof, return one of the maps with such changes shown thereon to the Commission.
If the map as submitted is approved by the Department or the Commission agrees with the changes made by the Department, the Commission shall, within thirty days after the receipt of the return of the map, so approved or changed by the Department, adopt such map as the Official Airports Plan and file a certified copy thereof with the county clerk and with the Department.
If the Commission does not agree with the changes made by the Department, it shall, within thirty days after the return of said map, file certified copies of the map as submitted to the Department and one of the maps with changes made by the Department shown thereon, with the county clerk. The county clerk shall present such maps to the county board at its next meeting. Such map shall then remain on file in the office of the county clerk until the next meeting of the county board, but for a period of not less than twenty days, and at that meeting the county board shall adopt one of the maps so filed as the Official Airport Plan. The plan prepared by the Commission shall be considered adopted if two-thirds of the membership of the Board votes in favor thereof, otherwise the map as changed by the Department shall become the Official Airport Plan. In either case, the county clerk shall place the map adopted as the Official Airport Plan, on file in his office and forward certified copies thereof to the Commission and the Department.
The airports designated on the map herein referred to as the "Official Airport Plan" shall be the airports to which this act applies, and it shall not apply to any other airports.
No changes shall be made in the location, or change in the class or type of the airports as shown in said Official Airport Plan, without the recommendation of the Commission, the approval of the Department and the consent of the county board.
If any Commission fails to prepare and submit the map showing the location, class and type of airports as aforesaid, the Department shall prepare such map and such map, when filed with the county clerk, shall become the "Official Airport Plan."
620 ILCS 50/53