Expired passport cannot be used for travel. Airlines will not allow to board the aircraft with the expired passport. While a Certificate of Naturalization serves as proof of U.S. citizenship, it is not a travel document and cannot be used in place of a passport. U.S. citizens will not be allowed to use their expired U.S. passport for direct return to the United States after June 30, 2022. If a U.S. citizen overseas has an expired U.S. passport, please contact your nearest U.S. Embassy or Consulate to apply for a U.S. passport.