Within a reasonable time after the filing of an application, the administrator shall issue a certificate to the applicant without a hearing thereon for that portion of the interstate operation that is within this state, upon such terms and conditions as he or she may deem proper and in the public interest, but the terms and conditions shall not conflict with those under which the federal certificate is issued. Any rights conferred upon the holder of any certificate issued under the provisions of § 39-11-19 — § 39-11-21 as well as the terms and conditions applicable thereto, shall apply only to intrastate operations performed in conjunction with interstate operations under the federal certificate, and the certificate issued under this section shall not be construed to grant to the holder thereof the right to operate otherwise as an intrastate carrier.