50 ILCS 615/35
In order to protect the wages, working conditions, and job opportunities of employees employed by the lessee of leased facility property used for airport purposes to perform work on the site of the leased premises previously performed by employees of the lessor on the site of the leased premises and who were in recognized bargaining units at the time of the lease, the lessee, and any subcontractor retained by the lessee to perform such work on the site of the leased premises, shall be required to pay to those employees an amount not less than the economic equivalent of the standard of wages and benefits enjoyed by the lessor's employees who previously performed that work. The lessor shall certify to the lessee the amount of wages and benefits (or their equivalent) as of the time of the lease, and any changes to those amounts as they may occur during the term of the lease. All projects at the leased facility property used for airport purposes shall be considered public works for purposes of the Prevailing Wage Act.
50 ILCS 615/35