California Code, Public Utilities Code - PUC § 21410

Every airman shall keep any certificate, permit, rating, or license required for him by the United States in his personal possession when he is operating within the state.  He shall present it for inspection upon the demand of any peace officer, any other officer of the state or of a political subdivision, or member, official, or employee of the department, authorized by Section 21252 to enforce the aeronautics laws, or any official, manager, or person in charge of any airport upon which the airman lands, or upon the reasonable request of any other person.