620 ILCS 5/78
All moneys hereafter received by this State, or by the Department for and on its behalf, under any of the laws of this State pertaining to aeronautics, including, without limiting the generality of the foregoing, all moneys obtained for certificates, permits or licenses, except those funds which are held by the State Treasurer as ex-officio custodian under the provisions of Section 40, shall be deposited in the State treasury and set apart as a special fund to be known as the Aeronautics Fund. The Aeronautics Fund shall be used, subject to appropriations made from time to time, only for such purposes as may be specified under the laws, if any, of the United States, heretofore or hereafter enacted or amended, providing for federal aid in the establishment of public airports, and otherwise only for the regulation and supervision of aeronautics in this State, and the administration and enforcement of the laws of this State pertaining to aeronautics.
620 ILCS 5/78