It's a shame that even smokers (like myself) don't actually realise how small their addiction is. Despite sometimes smoking 20 a day, I can also go for a day or so without even thinking about it. I've smoked for 10 years so don't try and tell me I don't have an addiction...
When you sleep your body manages quite nicely without smoking, the craving doesn't even wake you. Most people can even make it downstairs and put the kettle on or be on their way to the bus stop before lighting up - after a good 8-12 hours without a smoke.
The point I'm try to make is ANYONE can go for an UNLIMITED amount of time without smoking... It is not a basic human need. If you actually think about it (if you're a smoker) the craving isn't THAT bad. You feel it, but you deal with it.
A certain best selling quit smoking book goes further into these points and I recommend it.
In the mean time, start thinking about how your life is being dominated by a drug if you can't manage 12 hours on a plane and think SERIOUSLY about how that makes you feel.
One more point (from the book) ..... The very act of smoking is to make the smoker feel like a NON-smoker does.... The non-smoker does not have any craving, just like the smoker doesn't after finishing their cigarette. Crazy right?!
Kind of makes you think about cutting out the middle man and just feeling like a non-smoker all the time...