A child under 16 could be sat next to a paedophile in a train, a bus, an underground carriage, a McDonalds, a cinema, a theatre, not to mention a church bench, a school bench, or sports changing room. Moreover, despite what the Daily Mail might think, the immense majority of cases of underage victims of sexual assault and rape are the victim of someone they actually know rather than someone unknown hiding behind the bush. Paedophile abuse is a terrifying reality, but to my knowledge, suspected cases occurring on planes represent an infinitesimal part of those, and in the cases that I remember, the children did not happen to be unaccompanied. If anything, because perversion is often associated with cowardliness, planes are probably not great for those monsters as they cannot easily escape if found out. In the very rare cases when such atrocities have occurred onboard, I am not aware that people have blamed the airline, and indeed why would they. I do not really see what is the argument to suggest that the airline would be responsible for the criminal behaviour of an individual onboard its plane any more than a McDonalds or TfL would be when a pervert acts in their restaurant/underground carriage. As long as the airline (or anyone else) acts swiftly and ensures the child is protected from the suspect and that suspect safely delivered to authorities upon landing, it seems to me that they will have acted fully reasonably. It is only when institutions try to cover things up, fail to report accusations of sexual assault (or worse try to actively discourage victims from reporting them) or let suspects escape negligently that they are - very rightly - blamed.