70 ILCS 1305/1

The Commissioners of any park district which has or may hereafter adopt, "An Act authorizing Park Districts to acquire, establish, construct, maintain and operate airdromes, airports, and landing fields for aircraft, and authorizing the exercise of the power of eminent domain and permitting the levy of a tax therefor," approved June 24, 1929, and which is actually operating an airport, landing field or airdrome thereunder may by ordinance provide that within an area of two (2) miles from any airport, landing field or airdrome, such distance to be measured at a right angle from any side, or in a radial line from the corner of any established boundary line of such airport, landing field or airdrome, to restrict the height of any structure upon the relationship of one (1) foot of height to each twenty (20) feet of distance from such boundary line.