Section 40C. In a city airport approach regulations may be adopted, amended or repealed only by action of the city council, and in a town only by vote of the town, at a meeting called for the purpose, and in either case only after a public hearing held by the city council of the city or the selectmen of the town, at which hearing all persons who might be affected in their property by the regulations, all inhabitants of the city or town, all persons liable to taxation therein and all inhabitants of adjoining cities and towns shall have an opportunity to be heard. At least fifteen days’ notice of the time and place of the hearing shall be published in a newspaper of general circulation, if any, in the city or town. Airport approach regulations may be adopted by a city or town although the airport the approaches to which they are designed to protect is located in another city or town.