One can sympathize with the poor nicotine addict as his nicotine level drops lower and lower and he gets desperate for a fix, but the smoker should not be allowed to trample on the rights of the nonsmoker.
For some reason (the nicotine euphoria?) the smokers are often inconsiderate boors. After taking their drag, they hold the smudge away so that the acrid smoke curls up and irritates someone else's nose and eyes and lungs.
They cause innumerable fires and damage to floors, furniture and people with staggering costs. Smoking helps kill half a million people a year. Why society has so long tolerated this deadly habit is a tribute to the power of advertising and of the tobacco company money.
Fire of any kind is a danger on board a ship or aircraft. There is no law mandating smoking there, but there is one on not smoking. The addicts should be told of the law and warned in advance of the flight so if they cannot tolerate the time involved, they can take another flight--or walk.