50 ILCS 615/30
With respect to employees assigned to work on the premises of leased facility property used for airport purposes and who are not otherwise members of an existing bargaining unit cognizable under the National Labor Relations Act, and where not otherwise prohibited by applicable law, the lessee shall negotiate in good faith, with any union that seeks to represent its employees, for a labor neutrality and card check procedure agreement. The agreement shall apply only to employees actually assigned to work on the premises of the leased facility property used for airport purposes and shall have no applicability to employees not so assigned. The agreement shall contain provisions accomplishing the following objectives: resolution by a third party neutral of disagreements regarding bargaining unit scope, inclusions, and exclusions; determination of the existence of majority support for a bargaining agent by means of a card check procedure; employer neutrality; prohibition of coercion or intimidation of employees by either the employer or the union; and a prohibition on strikes, work stoppages, or picketing for the duration of the agreement.
50 ILCS 615/30