(a) In addition to or instead of the pledge of revenue and income of the airport authorized by Subchapter C, a municipality may impose and pledge to the payment of the operation and maintenance expenses of the airport a continuing annual ad valorem tax at a rate sufficient for that purpose, as provided in the ordinance authorizing the issuance of bonds under this subchapter.
(b) A tax under this section:
(1) must be imposed at a rate within any limit contained in the municipal charter; and
(2) may not be used for the payment of the principal of or interest on the bonds.

(c) The proceeds of a tax pledged under this section shall be used annually, to the extent required by or provided in the ordinance authorizing the bonds, for the operation and maintenance of the airport.