The board of supervisors of such county, acting through its county port authority, and the governing authorities of the municipality in which the port of entry is located, acting through its port commission, may, in their discretion and acting jointly, enter into a contract or contracts for the development, construction, repair, maintenance or operation of any seaports, wharves, piers, docks, ways, elevators, compresses, warehouses, tourism facilities, service facilities, roadways, floating dry docks, graving docks, marine railways, tugboats, and water, air and rail terminals and other structures, facilities and lands needful for the convenient use of the same in the aid of commerce, or any other property at the port of entry under the joint jurisdiction of said county port authority and such port commission under such terms and conditions as both bodies may deem best economically to the city and county wherein the port of entry is located. In the letting of contracts, and in advertisement for bids thereon, for the development, construction, repair, maintenance or operation of any structures, facilities and lands acquired pursuant to any of the provisions of this chapter, the said board of supervisors, the governing authorities of the said municipality, the county port authority and the municipal port commission shall comply with all the requirements of the general laws of the State of Mississippi governing the advertisement for bids and letting of contracts by county boards of supervisors. However, where the rentals provided in a lease will be sufficient to fully retire the cost of the particular facility, contracts for the construction, repair, maintenance and operation of the facility may be negotiated and consummated with the lessee of the facility without the necessity of advertising and obtaining competitive bids therefor. The county port authority is given full power and authority to employ engineers, attorneys and other professional and technical assistance in and about the operations, development and advancement of harbors and ports of such county, and to pay reasonable compensation therefor, such employment and compensation therefor to be approved by the board of supervisors of such county. The county port authority, and the port commission of the port of entry are jointly vested with the power and authority herein conferred, subject to the approval of the board of supervisors and the governing authorities of the municipality of all joint undertakings of such county port authority and port commission.