The State Highway Commission of the State of Mississippi is hereby fully authorized to convey and set over unto the United States government, or any of its subsidiary departments when approved by the Governor of the State of Mississippi, any and all rights of way or roads which it may own or possess or have authority over, conveying same exclusively to the United States government or conveying joint control thereof to the United States government for the purpose of aiding in the location, building, construction and maintenance of a national highway or parkway in the State of Mississippi.