У тайцев похоже изменился возраст совершеннолетия (на предыдущих страницах примерно то же самое было но про 16 лет).
Теперь судя по Тиматику и Википедии он 20 лет.
Minors (aged 19 or under) must meet one of the following conditions:
If the minor is travelling alone, the parents/legal guardians must inform the airlines at least 24 hours prior to travel, and fill the "Handling Advice for Unaccompanied Minor” form which includes details of the minor passenger.
Minors travelling with someone who is not their parent/legal guardian, or travelling with only one parent/legal guardian, must hold the birth certificate of the minor and a consent letter from the absent parent(s)/legal guardian(s) containing a copy of their passports that has been notarised and is in English or Thai. Custody papers or a copy of death certificate are required if one parent has sole custody or is deceased.
Minors travelling with both parents/legal guardians must hold an official relationship document, such as birth certificate.
