While in-flight smoking was banned on most commercial flights by the year 2000, "No Smoking" signs remain a permanent fixture on modern aircraft for several critical reasons. Legally, aviation authorities like the FAA and EASA require these signs to be visible to all passengers as a deterrent, as fire is one of the most dangerous emergencies that can occur at 35,000 feet. Even on brand-new planes like the Boeing 787 or Airbus A350, where signs are often printed labels rather than illuminated lights, they serve as a universal reminder for first-time travelers or those from cultures where smoking in confined spaces is more common. Furthermore, aircraft still feature ashtrays in lavatory doors; this is a mandatory safety requirement so that if a passenger does illegally light up, they have a designated place to safely extinguish the cigarette rather than tossing it into a trash bin filled with combustible paper towels.