; (2) the designation of new units of special airspace over the wilderness areas or wilderness additions designated by section 131; or (3) the use or establishment of military flight training routes over the wilderness areas or wilderness additions designated by section 131. (g) Horses Nothing in this subtitle precludes horseback riding in, or the entry of recreational or commercial saddle or pack stock into, an area designated as a wilderness area or wilderness addition by section 131— (1) in accordance with section 4(d)(5) of the Wilderness Act ( 16 U.S.C. 1133(d)(5) ); and (2) subject to any terms and conditions determined to be necessary by the Secretary. (h) Withdrawal Subject to valid existing rights, the wilderness areas and wilderness additions designated by section 131 are withdrawn from— (1) all forms of entry, appropriation, and disposal under the public land laws; (2) location, entry, and patent under the mining laws