Passport Entry into the United States
All air travelers on international flights are required to present a valid passport, Air NEXUS card, or U.S. Coast Guard Merchant Mariner Document, or an Alien Registration Card, to enter or re-enter the United States. This includes U.S. citizens returning by air from Canada, Mexico, Central America, South America, the Caribbean and Bermuda. You can read more about this requirement on the U.S. Department of State website.
Please see these links for further information and assistance obtaining international travel documents: