Is a minor travel consent form required for domestic travel? No, a minor travel consent form is not required for domestic travel within the U.S. However, it is recommended that parents and/or legal guardians carry a notarized letter of consent when traveling with a child.
The traveling parent will need to carry a Child Travel Consent form (also known as a Permission to Travel Letter, Minor Consent to Travel, or Parental Consent to Travel form).
The US government places no restrictions or requirements on you when exiting or entering the country with your child. Many foreign governments might require require documentation for entry or international air carriers to board their plane.
Typically, minors under the age of 18 do not have to present identification for domestic U.S. travel. Airlines will accept identification from the responsible adult on behalf of the minor(s). For international travel, minors under the age of 18 must present the same travel documents as the adult.
You should obtain a child travel consent letter granting you permission from the absent parent to leave the country with your child (having it notarized is not required, but highly recommended).
While the US does not legally require a parental consent form, US Customs and Border Protection strongly recommends one. Here's the advice from their Web site, bolding mine:
The letter of consent, preferably in English and notarized, from the other parent (if the child is traveling with one custodial parent) or signed by both parents (if the child is traveling with a guardian or alone) should say: "I acknowledge that my child is traveling outside the country with the name of the adult ...
How to fill out the Travel Consent Form for Minor Child - Parent Authorization? Enter the parent's name and relationship to the child. Provide the child's full name and date of birth. Input the details of the accompanying adult. Specify the travel dates and destinations. Sign the form as the consenting parent.
Consent to travel A child travel consent form has to be signed by both parents or legal guardians and has to contain: The child's basic information (name, gender, birthday, and place of birth) Both parents' or legal guardians' contact information. The traveling arrangements.
The letter should say: "I acknowledge that my child is traveling outside the country with the name of the adult with my permission." A parent who frequently crosses the border by land with a minor should always carry a letter of permission from the other parent.