La. R.S. § 2:261

The police juries of the various parishes, and the governing authorities of municipalities may dedicate and expend not to exceed one-half mill for any one year, out of their general alimony tax, may anticipate the tax, may borrow money and issue negotiable certificates of indebtedness payable therefrom bearing interest at a rate not exceeding six percent per annum, and for not exceeding ten years from date, payable annually or semi-annually, for the acquisition, improvement, maintenance, and support of airports and landing fields, or acquiring the same to be donated to the United States for military purposes, military posts, and flying fields, and may pledge the tax so dedicated to the payment of the certificates and the interest thereon. When the tax is so pledged it shall be annually assessed and collected and be used only for the payment of the certificates of indebtedness and the interest due thereon.