54 LAWS OF MARYLAND. [CH. 13

cal subdivisions; provided, however, that in all such cases
under this sub-title, before any such airport zoning regulations
are adopted, revised, amended, supplemented or changed, all
such original, revised, amended, supplemented or changed air-
port regulations shall be submitted to, and be approved by, the
governing body of the political subdivision or political sub-
divisions in which such airport is wholly or partially located
or by a joint board, if such joint board exists, created under
the provisions of sub-paragraph (3) of this Section 60 by the
political subdivisions involved. If the governing body of the
political subdivision in which the airport is wholly or partially
located shall approve the same, then such rules and regula-
tions, and all amendments thereto, shall thereupon become
valid and effective and shall thereafter have the force and
effect of law. If the governing body of the political subdivi-
sions in which the airport in wholly or partially located does
not approve the same, it shall notify in writing the political
subdivision, submitting the same, of such disapproval with its
reasons therefor. The action of the governing body of the
political subdivision in which the airport is wholly or partially
located on such rules and regulations or any amendments
thereto shall be final and binding. In every case of the sub-
mission of any such rules and regulations, or amendments
thereto, the governing body of the political subdivision in
which the airport is wholly or partially located shall act
thereon in not less than sixty days from the date of such sub-
mission and if it does not act thereon within that time, then
the same shall become valid and effective without the approval
of the governing body of the political subdivision in which the
airport is wholly or partially located. In case of conflict with
any airport zoning or other regulations adopted by any other
political subdivision, the airport zoning regulations adopted
pursuant to this sub-paragraph shall prevail.

(5) All airport zoning regulations adopted under this sub-
title shall be reasonable, and none shall require the removal,
lowering, or other change or alteration of any structure or tree
not conforming to the regulations when adopted or revised, or
otherwise interfere with the continuance of any non-conform-
ing use.

61. Permits and Variances.

(1) Permits. Where advisable to facilitate the enforcement
of airport zoning regulations adopted pursuant to this sub-
title, a system may be established and regulations may be
adopted by any political subdivision for1 the granting of per-
mits to establish or construct new structures or new uses of
land or structures or to replace existing structures or uses