Michigan Compiled Laws, Chapter 259. Aviation § 259.89a

Sec. 89a. Sections 86 and 87a  1 do not apply to landing areas designated and operated for the exclusive use of either ultralights or balloons. A landing area for ultralight or balloon use shall not be established, without commission approval, within 5 nautical miles of a public use facility certified by the commission. For the purposes of this section, “established” means any facility that is used or intended to be used for the operation of balloons or ultralights more than 10 times in any 12-month period.