The only plane on 9/11 to not hit the target was United Airlines Flight 93.
several passengers and flight attendants learned from phone calls that suicide attacks had already been made by hijacked airliners
Phone calls made by the passengers stopped the hijackers from achieving their goal.
All flights are non smoking, but the illuminated no smoking symbol is still there.
Reduce the hijack threat by replacing the now obsolete no smoking sign with a single, global, emergency telephone number, which works in all countries.
The use of digital telephone exchanges makes it a simple affair to have a single global emergency telephone number.
Countries that refuse to adopt the global number should be seen as being unsafe for travellers.