The District has power to acquire and accept by purchase, lease, gift, grant or otherwise any property and rights useful for its purposes and to provide for the development of channels, ports, harbors, airports, airfields, terminals, port facilities and terminal facilities and merchandising, commercial and industrial areas incidental to the ownership and operation of an airport terminal facility adequate to serve the needs of commerce within the District. The District may acquire real or personal property or any rights therein in the manner, as near as may be, as is provided for the exercise of the right of eminent domain under the Eminent Domain Act; except that no rights or property of any kind or character now or hereafter owned, leased, controlled or operated and used by, or necessary for the actual operation of, any common carrier engaged in interstate commerce, or of any other public utility subject to the jurisdiction of the Illinois Commerce Commission, shall be taken or appropriated by the District without first obtaining the approval of that Commission. The District has the power to lease, sell, exchange and mortgage real and personal property for any of the purposes for which it may acquire property under the terms of this Act. Any conveyance or mortgage by the District shall be signed by its Chairman and attested by its Secretary.