How do I write a consent letter for my child to travel? Know what documents a child needs to travel to or from the U.S. All children, including infants, must have their own travel documents.The intention of this letter is to provide consent for a minor child to travel without the company of both legal parents. A child travel consent form allows a minor to travel alone or with another person or group. We will be sharing some family travel tips about what documentation is needed, such as a travel consent letter, for international travel with a minor. Passport control would generally be the ones asking. However, airlines can also ask for it.