The privileges granted by this section and section
1317 of this title in respect of aircraft registered in a foreign country shall be allowed only if the Secretary of the Treasury shall have been advised by the Secretary of Commerce that he has found that such foreign country allows, or will allow, substantially reciprocal privileges in respect of aircraft registered in the United States. If the Secretary of Commerce shall advise the Secretary of the Treasury that he has found that a foreign country has discontinued, or will discontinue, the allowance of such privileges, the privileges granted by this section and such section
1317 shall not apply thereafter in respect of aircraft registered in that foreign country.