The local police authorities of any city, incorporated town or county shall have jurisdiction on the premises of any airport, drop zone or landing field operated hereunder, either individually or jointly and the State Police shall have jurisdiction to investigate any aircraft accident. In the exercise of such jurisdiction the State Police and officers of the department of law enforcement of any city or county with an optional form of government may enter with immunity and without a warrant upon private property for the purpose of conducting such investigations. This section shall not repeal the provisions of any city charter in conflict herewith.