The Board, if it finds that the erection of such structure will not be dangerous to aircraft using the airways of this Commission, shall issue the permit requested; but if it shall find that the erection of such structure will create a hazard to aircraft using such airways, it shall refuse the issuance of such a permit. The Board may, as a condition to the issuance of any permit, require the installation and maintenance of warning lights and any other devices which may be reasonably required to reduce the hazard which might be presented by the erection of such structure.