There may be something to consider: when a Brazilian citizen child is traveling alone or without all of the child’s parents on a Brazilian passport, things may work differently than when the same Brazilian child appears to be traveling with two parents or is using a non-Brazilian passport.

Brazilian law requires any minor who is a Brazilian citizen — even dual nationals who are both Italian and Brazilian citizens — to have permission from each parent to travel within Brazil or exit the country. [Enter the country is a different story, but then there is the “within Brazil” part.] When the Brazilian minor travels with only one parent or without either parent, they must have two original written authorization letters from each absent parent and carry a copy of the child’s birth certificate or have an annotation in his/her Brazilian passport authorizing travel alone or with only one parent. Or something like that. I don’t know how likely Schengen passport control or the airline reps may consider such kind of thing just because of the Brazilian passport use, but there are instances where they could bring it up.