65 ILCS 5/11-101-4

(a) As used in this Section, "joint-use airport" means an airport owned, in whole or in part, by a county, located in a county with a population of over 200,000 bordering the Mississippi River, and used by both military and civilian aircraft. (b) A municipality may not levy or collect any use, occupation, privilege, or excise tax, including, but not limited to, a parking excise tax, on any transaction that occurs on the premises of a joint-use airport or on property that exclusively serves a joint-use airport. This subsection (b) is a denial and limitation of powers and functions under subsection (g) of Section 6 of Article VII of the Illinois Constitution.