My brother is autistic and my parents won't take him on a plane. Because they don't know how he will react. My brother has hypersensitive hearing if a baby starts crying he would freak out. In such an enclosed space that would be an issue. However, my brother is severely autistic and now that I think about it I haven't seen a severely autistic person on a plane. My guess is the parents of a severely autistic person know better then to go on a plane. You probably won't notice a high function autistic person on a plane. Aside from the lack of eye contact they would appear pretty normal.