"Why do Chinese air travellers get angry and violent so easily?"
Reason is simple: They are brought up as little emperors and empresses; all their family members give in to all their demands and if they don't get what they demand, they kick and punch their elders, as seen so often in public. They grow up with the idea that everyone must give in to them and they take that into society wherever they go. They don't just hurt airlines staff, they also hurt doctors and nurses and smash office equipment, even drag traffic policemen on their car bonnets, and beat up 'chengguan'! That's the price society pays for poor parenting and the one-child policy!