Va. Code § 5.1-35
All powers, rights, and authority granted to counties, cities, and towns under this article may be exercised and enjoyed jointly by any two or more of such political subdivisions within or without the territorial limits of either or any of them, or if one or more of such political subdivisions is a county, then within such county or one of such counties, and the political subdivisions so acting jointly may enter into such agreements with each other as may be necessary or proper for the exercise and enjoyment of the joint powers hereby granted, and for joint action in carrying out the general purposes of this article. The powers granted by this section shall include the power to seek and obtain loans for the purpose of capital improvements to any airport or landing field established pursuant to this article.
Va. Code § 5.1-35