When my kids were underage and traveling internationally, we used to give them a notarized letter stating they had permission to travel, this policy being recommended by the US Department of State.
In perhaps a dozen entries and exits (to Europe, Asia, and North America), no official ever asked to see this letter.
Edit (21/01/17): See my edit below for the original answer.
TL;DR: there’s a document you need which can be found online. Original answer below.
to or from a non-Schengen member state
Your answer is already in the question. While an unaccompanied minor could be a special case, you’re accompanied by your brother, and you’re traveling within Schengen. If they notice you’re underage and want to say something about it, they’ll look up and see you’re travelling with your brother. He’s the adult who’s responsible at that point.
To officially put on paper that your brother is responsible, your parents could fill in and sign an official form if Portugal has one. This typically is a form that can be downloaded from your government’s website, stating who is allowed to travel with you to another country (and is responsible for you). This paper should be relative easy to access, I can’t imagine needing to go to the embassy for this. If I remember correctly, Belgium gives them out in the city hall. This might be a starting point for you to find where those are distributed.
EDIT: link to the document: http://www.sef.pt/portal/v10/en/aspx/apoiocliente/detalheApoio.aspx?fromIndex=0&id_Linha=4350 (bottom of page)
Source: personal experience on flying and trips with underage people. School trips to other countries (from Belgium) required this form while underage
Credit:stackoverflow.com‘
4 Mar, 2024
4 Mar, 2024
5 Mar, 2024