My son is autistic and like the approximately 1 in 68 children on the spectrum is prone to having melt downs. But on a flight back from LAX to London via Frankfurt (his first long-haul) two weeks ago he coped fine, even after we got caught up in the strikes at FRA, were re-routed several times losing our luggage on the way, and being tired, hungry, frazzled. The (fantastic) LH crew complimented us on him being so well behaved, not even realising he was autistic. It could so easily have gone the other way.. you never know. Its neither ethical or possible to discriminate in that way with any degree of efficiency and IMHO its pointless to have the discussion, frankly - if you cannot reliably screen mentally ill pilots like Andreas Lubitz how the heck are you going to screen pax?