I don't want to be too Basil Fawlty-ish about it, but the level of rudeness amongst passengers is a direct result of air travel being far too cheap and so people "who have never even sat on chairs before" (Copyright J. Cleese) are flying here there and everywhere.
Double the price of tickets and you will:
1) Cut rudeness
2) Cut air-rage
3) Cut stress on cabin crew
4) Cut fatigue on pilots (less flights, less pressure on roster)
5) Cut pressure on ground staff ranging from engineers to check-in people.
6) etc etc.
The more complicated maths which I am not competent to perform is: would the reduction in air traffic, but the doubling of revenue from each seat, be enough to keep the industry viable, or would it cut pilot numbers, and those of related industry workers?