Airline Requirements are TSA Requirements
Most airlines require the same identification to travel that the U.S. Transportation Security Administration requires to get through its checkpoint. TSA requires a state or federally issued photo identification with name, date of birth, gender, expiration date and a tamper-resistant feature.
Lost, Stolen, Missing ID
It's still possible to travel if you don't have one of the TSA's acceptable forms of identification. A TSA officer will ask you additional questions and it's likely they'll conduct additional screenings of you and your luggage. Without an ID, the TSA has the ability to prevent you from flying.
Traveling With a Minor
The TSA requires only adults (18 and older) to carry identification. But, some airlines require minors traveling without an adult to carry some form of ID, although they're less stringent about who issues the ID. For example, Continental Airlines will accept a school ID, library card or birth certificate, as of 2010, from a younger traveler.
International Travel ID Requirements
Each country you travel to will have different requirements for entry. Most will require a passport, some will also have visa and health restrictions. The U.S. Department of Homeland Security recommends you contact that country's embassy or consulate to find out what documents are required.
International Travelers Flying Within the United States
The TSA will accept Permanent Resident Cards as an acceptable form of identification to travel. But other international travelers flying within the United States will always have to show their passport.
