Director of aeronautics. There is hereby established and created the office of director of aeronautics within the department of aeronautics. The director shall be appointed by the commission, to serve for an indefinite term, during his efficient, honest and businesslike execution of his duties. He shall be appointed with due regard to his fitness and by reason of his aeronautical knowledge and practical experience in the field of aeronautics. He shall devote his entire time to the duties of his office as required and prescribed by this act, and shall not be actively engaged or employed in any other business, vocation, or employment, nor shall he have any pecuniary interest in or any stock in or bonds of any civil aeronautics enterprise. He shall receive such compensation as the commission may determine and shall be reimbursed for all traveling and other expenses incurred by him in the discharge of his official duties.