Any agency, municipal corporation or political sub-division of this state which owns or operates a public airport is authorized to control the movement of aircraft upon the ground or surface of such public airport and forbid the taking off of aircraft from or landing at such public airport when, due to the existence of any of the conditions specified in this Act, such movement or flight will endanger the public safety, health, welfare or common defense, and may, by ordinance or resolution of its governing body, delegate such authority to one or more of its employees who are regularly employed in the management or operations of the public airport; provided, no such authority shall be delegated to any employee unless the qualifications of such employee as to his training, knowledge and experience in the matters and conditions specified in Section 3 and his ability to properly exercise the authority proposed to be delegated, are first submitted to and approved by the Department of Transportation. The Department of Transportation may examine any such employee in regard to his qualifications as to the matters hereinbefore specified.