The cost of planning, acquiring, establishing, developing, constructing, enlarging, improving, maintaining or equipping an airport or air navigation facility, or the site therefor, including buildings, structures and other facilities incidental to the operation thereof or relating thereto, the acquisition of avigation easements, and the acquisition or elimination of airport hazards, may be paid for wholly or partly from the proceeds of the sale of bonds or other obligations of the municipality, as the governing body of the municipality shall determine. The bonds or other obligations may be issued by a county in accordance with title 5, chapter 11 [repealed] and by an incorporated city or incorporated town in accordance with title 7, chapter 36 [repealed]; provided, that any landing fees, concession fees, rents, charges, or any other revenues derived from the operation of an airport, pledged as security for the bonds, that are fixed and established by the provisions of a lease or contract, shall not be subject to revision or change during the term of such lease or contract except in the manner provided in the lease or contract.