Western Hemisphere Travel Initiative U.S. Customs and Border Protection Western Hemisphere Travel Initiative WHTI Western Hemisphere Travel Initiative Western Hemisphere Travel Initiative U.S. Customs and Border Protection Western Hemisphere Travel Initiative WHTI U.S. ustoms and Border Protection Western Hemisphere Travel Initiative Western Hemisphere Travel Initiative Western Hemisphere Travel Initiative WHTI Western Hemisphere Travel Initiative Western Hemisphere Travel Initiative WHTI Western Hemisphere Travel Initiative WHTI Western Hemisphere Travel Initiative WHTI requires U.S. citizens to use a passport WHTI Western Hemisphere Travel Initiative Western Hemisphere Travel Initiative WHTI Western Hemisphere Travel Initiative CBP WHTI WHTI DHS WHTI Western Hemisphere Travel Initiative U.S. ustoms and Border Protection Western Hemisphere Travel Initiative WHTI Western Hemisphere Travel Initiative WHTI U.S. ustoms and Border Protection WHTI Western Hemisphere Travel Initiative DHS Western Hemisphere Travel Initiative CBP Western Hemisphere Travel Initiative Western Hemisphere Travel Initiative Western Hemisphere Travel Initiative WHTI Western Hemisphere Travel Initiative More on Land and Sea Travel U.S. ustoms and Border Protection Western Hemisphere Travel Initiative