Mont. Code § 67-10-303
Any authority vested by this chapter in a municipality or in the governing body thereof for the planning, establishment, development, construction, enlargement, improvement, maintenance, equipment, operation, regulation, protection, and policing of airports or other air navigation facilities established, owned, or controlled or to be established, owned, or controlled by the municipality may be vested by resolution of the governing body of the municipality in an officer or board or other municipal agency whose powers and duties must be prescribed in the resolution. However, the expense of such planning, establishment, development, construction, enlargement, improvement, maintenance, equipment, operation, regulation, protection, and policing is a responsibility of the municipality.
§ 67-10-303, MCA