TSA won't take them, but should they ask about the minor children, it's best to be prepared. We don't know where this parent lives or what kind of custody they have. Some states have a law that the non custodial parent must have permission to take the children out of state. Also, if the parent traveling does not have medical authority, then they should also have a notarized letter giving permission to make health care decisions for the child in case of emergency.