During all my travels, I have only had one serious incident about 20 years ago from CPH to the old BKK, upstairs on a Thai 747-400, where a Norwegian decided he wanted to try to open the upstairs door at about 36,000 feet. Luckily, two stewards and a couple of us passengers subdued him and he was handcuffed to his seat. He was greeted by the police in Bangkok.