620 ILCS 10/2
Immediately upon the existence of a state of military emergency, and coincident with the duration thereof, the Department is vested with emergency police power to prohibit, restrict and control the initiation of non-scheduled civil aircraft movements, including the assignment of flight priority classifications, to the extent that it is requested to do so by military or civil authority of the federal government as required to supplement otherwise existing air traffic control facilities in order to achieve the degree of military air defense effectiveness determined by the federal military and defense commander to be required under the circumstances and conditions obtaining at any time during the existence of the military emergency.
620 ILCS 10/2