(70 ILCS 5/16) (from Ch. 15 1/2, par. 68.16)
    Sec. 16. Pre-existing public agencies. Except as otherwise provided in this Section, in case any airport authority organized hereunder shall be coterminous with, or shall include within its corporate limits, in whole or in part, any pre-existing public agency authorized to own, operate and maintain a public airport and to levy taxes for any such purpose, and in fact owning, operating and maintaining a public airport or public airport facility located within the corporate limits of such airport authority, such public agency other than any airport authority acquired by a Metropolitan Airport Authority, shall be paid, upon such terms as may be agreed upon by its corporate authorities and the board of commissioners of such airport authority, but in no event shall such public agency be paid in excess of its investment or for any funds advanced to such public agency, or otherwise paid or expended, either directly or indirectly, by the state or federal governments for the acquisition of the land used for such airport or for any such existing airport improvement or facility. The terms of payment shall provide for payment in full within not more than 20 years from the date of such agreement. However, a Metropolitan Airport Authority shall have no authority to acquire a public airport or public airport facilities of an airport which is operated by a municipality with a population over 500,000.
    In case the amount and terms of payment are not so determined by agreement, the board of commissioners of the Authority shall cause a description of such airport and such existing improvements and facilities to be made together with an estimate of the previous actual expenditures of such public agency therefor, and shall tender payment of the total amount so estimated in writing to such public agency. Such tender shall provide for payment by the Authority of the amount tendered within 5 years from the date thereof, any part of the sum remaining unpaid after 12 months from the date to bear interest at a rate not to exceed the maximum rate authorized by the Bond Authorization Act, as amended at the time of the making of the contract. In case such tender is not accepted in writing by the corporate authorities of such public agency within 30 days after the same is made, the Authority by its board of commissioners shall file a petition in the circuit court of a county in which the Authority and such public agency are both situated, making such public agency a party defendant thereto, setting forth a description of such airport, airport improvements and facilities, the estimated amount of such previous expenditures by the defendant, the fact of such tender having been made and the date thereof, and praying that there be determined by the circuit court the true amount of such prior expenditures by such public agency. A copy of the petition shall be served upon the presiding officer of such public agency within 5 days after the filing of such petition, and upon presentation to the court of proof of such service, the petition shall be set for hearing within not less than 10 nor more than 20 days. Such hearing may be continued from time to time upon the request of the petitioner or of the respondent, and, upon the hearing, the circuit court shall consider such evidence as may be submitted by the parties and shall determine the amount of such actual previous expenditures made by such public agency. The amount so determined shall be conclusive as between the parties, and shall be paid by the airport authority within 5 years after the entry of the order making such determination, any part of the sum remaining unpaid after 12 months from the entry of the order to bear interest at a rate not to exceed the maximum rate authorized by the Bond Authorization Act, as amended at the time of the making of the contract. When paid the sum shall be accepted by the public agency as full payment for such airport and existing improvements and facilities.
    Moneys received by any such pre-existing public agency from such airport authority in consideration of the conveyance or transfer of any such airport property or airport facility shall be held and used by it, in full or to the extent required, for the repayment of its outstanding, lawful airport indebtedness, as the same matures.
    Upon the determination of the amount of payment to be paid by the authority to any such public agency and the approval thereof and the terms of payment by the corporate authorities of such public agency and the board of commissioners of the airport authority, or, in case the amount and terms of payment are not determined by agreement, upon the tender by the Authority as above provided, the airport authority shall succeed to the interest of such public agency in such airport property or facility and shall appropriate and use any such airport property or facility in accordance with its authorized corporate objects and purposes, and any such pre-existing public agency which is coterminous with, or is wholly included within, the corporate limits of an airport authority, shall cease to exercise any power in respect to public airports; and any such public agency which is only in part within such airport authority shall not thereafter own, operate, maintain, manage, control or have an interest in any public airport or airport facility within such airport authority.
    Except in the case of any such pre-existing public agency which, at the time an Authority is established, owns and operates a public airport located within the corporate limits of the Authority, and then only for the period of time required for the acquisition of such airport by the Authority as above provided, and except as otherwise provided in this Section no public agency shall own, operate or maintain a public airport within the corporate limits of the airport authority.
    In case the airport owned, operated and maintained by any pre-existing public agency is located upon land owned by another public agency which by lease or agreement has authorized the establishment of such airport upon its land, the airport authority upon acquiring such airport, or concurrently with its acquisition, may acquire title to such land by agreement with the public agency having title thereto and if the Authority is unable to agree with the public agency in respect to the value of the land, the Authority may acquire title thereto, free and clear from all airport improvements, leases, agreements and encumbrances, as is provided by Section 9 of this Act.
    Nothing in this Section shall prohibit a municipality with a population of over 500,000 from owning, operating and maintaining a public airport within the corporate limits of a Metropolitan Airport Authority.
    With respect to instruments for the payment of money issued under this Section either before, on, or after the effective date of this amendatory Act of 1989, it is and always has been the intention of the General Assembly (i) that the Omnibus Bond Acts are and always have been supplementary grants of power to issue instruments in accordance with the Omnibus Bond Acts, regardless of any provision of this Act that may appear to be or to have been more restrictive than those Acts, (ii) that the provisions of this Section are not a limitation on the supplementary authority granted by the Omnibus Bond Acts, and (iii) that instruments issued under this Section within the supplementary authority granted by the Omnibus Bond Acts are not invalid because of any provision of this Act that may appear to be or to have been more restrictive than those Acts.
(Source: P.A. 86-4.)