Children's Travel Consent Letter Apostille
A travel consent letter must be drafted, signed, notarized, and certified by an apostille from the State office when one or both parents are unable to accompany a minor child on travel.
Not only does the airline demand a travel consent letter, but most nations will also need that this letter be apostille-certified to establish that the official (notary public) met with the document's signer. The parent who is not accompanying the kid on the trip must sign and have the travel consent letter notarized. If neither parent is accompanying the minor kid on the trip, both parents' signatures must be signed and notarized.
You can find examples of travel consent letters online, or the airline can offer you with a copy to fill out.