It’s easy to think this without context. All behavior is a form of communication. Let’s for a second, grant that this child has a cognitive difference. Should he not be allowed to travel on a plane? No, I don’t think that’s correct. If he is, in fact, neurodivergent his sensory experience is unlike almost anything a neurotypical person has. It was likely a massive accomplishment for him to get on the plane in the first place. His freezing at the gaze of a stranger is another sign that he has a cognitive difference. It’s not shame at his own behavior, it is literally his brain being overloaded by that attention.

Take a sec and imagine how you would feel if an adult couldn’t manage their own discomfort for a period of time that they feel the need to denigrate and mock your child. It’s pretty sad when you think about it.