The state shall not engage in works of internal improvement, nor lend money or its credit in aid as such, except as may be authorized by the Constitution of Alabama or amendments thereto; nor shall the state be interested in any private or corporate enterprise, or lend money or its credit to any individual, association, or corporation, except as may be expressly authorized by the Constitution of Alabama, or amendments thereto. When authorized by laws passed by the legislature the state may appropriate funds to be applied to the construction, repair, and maintenance of public roads, highways and bridges in the state. When authorized by appropriate laws passed by the legislature the state may at a cost not exceeding ten million dollars engage in the work of internal improvement, or promoting, developing, constructing, maintaining, and operating all harbors and seaports within the state or its jurisdiction, provided, that such work or improvement shall always be and remain under the management and control of the state, through its state harbor commission, or other governing agency. When authorized by laws passed by the legislature the state may engage in the construction, improvement, repairs and maintenance and operation of public airports, air landing fields and other air navigation facilities in the state of Alabama and may appropriate money or otherwise provide funds for this purpose. The adoption of this amendment shall not affect in any manner any other amendment to the Constitution of Alabama which may be adopted pursuant to any act or resolution of this session of legislature.