TSA does not require children under 18 to provide identification when traveling within the United States. Contact the airline for questions regarding specific ID requirements for travelers under 18.
I, ______________________________________________ (name of parent), am the ______ (mother) ______ (father) of __________________________________ , aged ____________ , and do hereby give my consent for (him)(her) to travel with __________________________________________________________________ (name/address of traveling ...
Children under 18 don't need an ID to fly domestically but do need a passport for international flights.
Do you need a notarized letter to travel with a child alone? In most cases of a single parent traveling out of the country with their child, the answer is yes you do need a notarized consent to travel letter. You can download your own customizable travel consent letter here.
You don't need any documentation. The only time you would need a birth certificate is if you were flying with them as a lap child. I just flew 3 southwest flights with my four year old and he was only asked what his name was by TSA. Didn't have to show anything.