; (2) the designation of new units of special airspace over the wilderness areas or wilderness additions designated by section 202; or (3) the use or establishment of a military flight training routes over the wilderness areas or wilderness additions designated by section 202. (g) Horses Nothing in this title 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 202— (1) in accordance with section 4(d)(5) of the Wilderness Act ( 16 U.S.C. 1133(d)(5) ); and (2) subject to such terms and conditions as the Secretary determines to be necessary. (h) Law enforcement Nothing in this title precludes any law enforcement or drug interdiction effort within the wilderness areas or wilderness additions designated by section 2 in accordance with the Wilderness Act ( 16 U.S.C. 1131 et seq.). (i) Withdrawal Subject to valid existing rights, the wilderness areas and additions designated by section 202 are withdrawn from— (1) all forms of entry, appropriation, and disposal under the public land laws; (2) location, entry, and patent under the mining laws; and (3) operation of the mineral materials and geothermal leasing laws. (j) Incorporation of acquired land and interests Any land within the boundary of a wilderness area or addition that is acquired by the United States shall— (1) become part of the wilderness area or addition in which the land is located