I am seeing more and more cases of drunk/high/crazy people causing disturbances on flights. It’s useful to prepare for such an altercation.
Here is an informative discussion about how the author handled a drunk and belligerent passenger seated next to him on the plane. I personally would have changed seats. You can’t escape a plane in the air. Moving as far away from the drunk guy as possible shows your attempt to deescalate the situation. If he presses the confrontation, he will be more clearly seen as the aggressor.
Do your best not to engage with the drunk and high people on your flight. It’s not worth the aggravation. Remember that protecting others on the flight isn’t your responsibility. Get yourself out of the hot seat and let the flight attendants deal with his obnoxious behavior.