The Department may issue an order granting or denying a certificate of approval of an airport or a restricted landing area, or the alteration or the extension thereof, without a hearing in the first instance, provided the Department shall have served upon the applicant, and any other persons, municipalities or other political sub-divisions affected, at least fifteen days before the entry of such proposed order, notice of the Department’s intention to enter such order, which notice shall state in reasonable detail the nature and terms of such proposed order and shall extend opportunity, on the part of those notified, to submit, within such fifteen days, objections to or comments upon the subject matter of such proposed order; written notice shall be given to the applicant, and written notice or in the alternative notice by publication in a newspaper published in the county in which the airport or restricted landing area sought to be established, altered or extended is, or is proposed to be located, shall be given to any other persons, municipalities or other political subdivisions affected; and after the entry of any such order, a copy thereof shall be served upon the applicant, those who, within the above specified 15 day period, object to or comment upon the subject matter of the proposed order and those who have entered their appearance in writing in the matter. Notice of the entry of the order shall be given to any other persons, municipalities, or other political sub-divisions affected thereby by serving a copy thereof upon them or in the alternative by publication in a newspaper published in the county in which the airport or restricted landing area sought to be established, altered or extended is, or is proposed to be located. If the applicant or any other person, municipality or other political sub-division which may be affected thereby, makes a written request for a hearing as to the validity or reasonableness of said order within fifteen days after the service or publication thereof, the Department shall prescribe a hearing thereon, which shall be held in the municipality or other political subdivision applying for a certificate of approval or, in case the application was made by a person other than a municipality or other political subdivision, at the county seat of the county in which the airport or restricted landing area sought to be established, altered or extended is, or is proposed to be situated. If no hearing is requested, as herein provided, such order shall take effect and become operative at the same time and in the same manner as in the case of an order entered after hearing, as provided in Section 57. No notice shall be necessary prior to the entry of an order approving the elimination of one or more runways or landing strips or approving a change in classification of a facility from that of an airport to that of a restricted landing area unless the application therefor shall indicate that there is an addition, extension or reorientation involved as will result in a change in the flight patterns theretofore obtaining. If any persons, corporations, or municipalities may be affected by any such change in the flight pattern from the pattern which shall have existed prior to any such addition, extension or reorientation, notice shall be given as provided in the first paragraph of this section.