620 ILCS 10/3
In order to implement and aid in the execution of such emergency police power the Secretary of the Department is authorized to delegate in writing, prior to the existence of a state of military emergency, to managers or operators of such commercial airports within this State as he determines to be appropriate, authority to prohibit, restrict or control as appropriate, during the existence of a military emergency, the initiation of non-scheduled civil aircraft movements from such airports and to assign flight movement priority classifications according to directives relating thereto issued by the Department compatible with currently effective standards or directives issued by appropriate federal military or civil authority. Such delegated authority shall include the authority to detain, in the name of the People of the State of Illinois, the person of any aircraft operator or pilot to the extent that such detention is necessary to accomplish the purposes of this Act.
620 ILCS 10/3