There are some important passport requirements for passengers traveling to the United States. From Jan. 20, 2010, it became mandatory for all airline passengers traveling to the United States to either obtain a visa or apply for an Electronic System for Travel Authorization for nationals of a country that participates in the Visa Waiver Program. This requirement applies to all passengers, even those in transit through the U.S. In other words, you now need a U.S. visa to simply change planes in the U.S.
Visa Waiver Program (VWP)
Nationals of certain countries can participate in the Visa Waiver Program (VWP). A link to the list of the approved countries can be found in the Resources section of this article. In addition to the counties on the list, citizens of Canada and the British Overseas Territories of Bermuda can travel to the U.S. without a visa. Nationals of countries that participate in the Visa Waiver Program must hold a Machine Readable Passport (MRP) to travel under the program. Holders of non-MRP passports must obtain a U.S. visa before traveling to the U.S. In addition to this requirement, the travel must be for business, pleasure or transit and the total stay in the U.S. can not exceed 90 days. A confirmed return or onward ticket is also required, along with a completed I-94W form. The I-94 form is available aboard the aircraft. You must have a U.S. address and zip code for where you are staying to fully complete the I-94W form. The final requirement is that the traveler complete the Electronic System for Travel Authorization.
Electronic System for Travel Authorization (ESTA)
All passengers traveling under the Visa Waiver Program must now apply for a Electronic System for Travel Authorization at least 72 hours before travel. You can obtain authorization online by following the link listed in the Resources section of this article. The application process takes 15 to 20 minutes and authorization is normally granted immediately, but may take up to 72 hours. Once granted, travel authorization is valid for multiple entries to the U.S. for two years, unless any answers to the "Yes/No" questions on the form change or a new passport is required. You are also required to visit the site again and provide advance passenger information to the U.S. government each time you travel to the U.S.
Travelers Requiring Visa to Enter U.S.
All other travelers not eligible to participate in the Visa Waiver Program require a visa prior to traveling to the U.S. Those needing a visa should contact the U.S. Embassy in their home country. If you require a visa, you must make an appointment at the U.S. Embassy for an interview. The process of applying for a U.S. visa can be lengthy, and you should allow at least two months to complete the process. Travelers arriving in the U.S. in transit to a foreign location are required to clear customs and immigration and are subject to U.S. regulation and laws. The U.S. does not issue same-day visas.