The aviation industry is now taking very seriously the growing menace posed by disruptive passengers. Airline pilots and flight attendants from around the world are calling on airlines to enforce tighter in-flight security measures and for law enforcement agencies to impose tougher penalties on offenders. Excessive drinking usually triggers the aggressive outburst. Other factors are nicotine deprivation, resentment of authority, a stress reaction to a fear of flying, and the stress generated by crowded airports and planes.