When boarding a domestic flight, the Transportation Security Administration takes the need for proper identification very seriously. Do not risk missing your flight, losing the money you spent on your trip, and passing up an exciting trip just because you don't have the proper identification in your pocket.
Government Issued Identification
According to TSA requirements, a passenger must have a federal or state-issued identification card to board a plane. This includes one of the following photo IDs: a driver's license; nondriver's identification card; passport; military ID card or permanent resident card. In order to get one of these identification cards or papers, you have to submit complete information and documentation about your identity, including birth certificate, social security card, and even utility bills in some cases to a government agency prior to your day at the airport. A TSA officer will not accept an identification card from a nongovernment entity.
ID Can't Be Expired
Keep in mind that your identification cannot be expired if you want to use it to get on a domestic flight. An expired date renders your identification invalid according to airport security, and you will not board your flight. Check the dates of your flights (both leaving and arriving back in town) as well as your ID to assure that it will still be valid for at least a week or two after the date you are scheduled to return.
Requirements for Children
Since children younger than 18 are not usually eligible to receive a state-issued driver's license or identification card, you can bring the child's original U.S. birth certificate instead. This proves the child's age. This is not required by the TSA for children travelling with an adult, but some airlines will ask for proof of a child's age, so check with your airline for its policy. Still, it is wise to get a kid's travel card for your child if you plan to travel with him often (see "Resources" for a link to a service that allows you to purchase this type of card).
If you are picking up or dropping off a minor at the airport to travel by himself, you must provide your own government-issued identification to the authorities as well.
If you can't provide an ID
If you have lost your ID or can't provide one for some reason, you will have to provide information to the transportation security officer performing document-checking duties. Passengers who are cleared through this process may be subject to additional screening. Be prepared for delays in this situation.