When traveling internationally, it's a good idea to get a consent letter from the parents indicating that you have their permission to travel with your grandchildren. Most likely no one will ask you for it, but you'll be glad to have a hard copy on you in a scenario where you can't get in touch with them.

Yes, children can fly with their grandparents both domestically and internationally, but you must carry specific documentation to avoid delays or suspicion of child abduction. For domestic flights, grandparents should carry a notarized Child Travel Consent Form signed by both legal parents, along with a copy of the child’s birth certificate to prove their identity. For international travel, this notarized consent letter is strictly required by customs and border protection agencies; it should clearly state the travel dates, destination, and the parents' contact information. Additionally, it is highly recommended to carry a Child Medical Consent Form, which authorizes the grandparents to make emergency medical decisions if the parents cannot be reached. Without these documents, airline staff or immigration officers have the authority to prevent the child from boarding or entering a foreign country. Always ensure the child has their own valid passport for international trips, and check with your specific airline for any additional "unaccompanied minor" protocols if the child is traveling as part of a larger group without a legal guardian present.