Sec. 16. The authority may negotiate terms and borrow money from any source under a loan contract, subject to the following requirements:
(1) The loan contract must be approved by resolution of the authority.
(2) The loan contract must provide for the repayment of the loan in not more than forty (40) years.
(3) The loan contract must state that the indebtedness is that of the authority, is payable solely from revenues of the authority that are derived from either airport operations or from revenue bonds, and may not be paid by a tax levied on property located within the state.