whats umcomfortable about e-cigs if ya dont mind me askin ?
for one thing not everyone knows what they are and will be thinking that someone is actually smoking a real cig. next is the fact that nobody knows for certain that the exhaled 'vapor' is 100% harmless. It may be free of smoke from plant material but it has delivered nicotine to the user and so it can be expected that some remains in the exhaled vapor.
'Smoking' is NOT a right you have just because you choose to do it and can afford your smokes. my last Mercedes was designed to and could do 120mph all day on the interstate highway but by golly there are laws that say I can't.
Flying is not a right either and the privilege can be taken from you rather arbitrarily, maybe not for trying to do your e-cig thing but if you got into a fight with someone over it you could kiss your e-cig smoking ass goodbye from commercial flights forever.
I drove taxi in a wealthy NY suburb, I picked up passengers that were denied their smokes during the flight & of course while waiting for their luggage; they'd get into my cab just begging to light up and considering their anxiety level I always allowed them to do so. I'd ask them to consider that they got into a fresh smelling car and the next passengers and to use the window as effectively as they could, I hate cig smoke but had to have compassion for their needs.