Mont. Code Ann. § 67-11-205

For the purpose of providing the joint board with moneys for the necessary expenditures in carrying out the provisions of 67-11-203 through 67-11-205, a joint fund shall be created and maintained, into which shall be deposited the share of each of the constituent public agencies as provided by the joint agreement. Any federal, state, or other grants, contributions, or loans and the revenues obtained from the joint ownership, control, and operation of any airport or air navigation facility under the jurisdiction of the joint board shall be paid into the joint fund. Disbursements from such fund shall be made by order of the board, subject to the limitations prescribed in 67-11-204 (2).