620 ILCS 5/45
The federal license, certificate, or permit, and the evidence of registration in this or another state, if any, required for an airman shall be kept in the personal possession of the airman when he is operating within this State and must be presented for inspection upon the demand of any passenger, or any peace officer of this State, any officer or authorized employee of the Department, or any official, manager or person in charge of any airport in this State upon which he shall land, or upon the reasonable request of any other person. The federal aircraft license, certificate, or permit, and the evidence of registration in this or another state, if any, required for aircraft must be carried in every aircraft operating in this State at all times and must be conspicuously posted therein where it may readily be seen by passengers or inspectors and must be presented for inspection upon the demand of any passenger, any peace officer of this State, any officer or authorized employee of the Department, or any official, manager, or person in charge of any airport in this State upon which it shall land, or upon the reasonable request of any person.
620 ILCS 5/45