Ya, I would have to agree with Puff... people seem to be a lot more uptight on planes these days.
I did read a blog somewhere where someone claimed to have used an ecig on a plane and not have to do it conspicuously. He claims that he waited until they were serving drinks and then he asked the stewardess if he could use his "smoking cessation" device. He explained how it worked and demoed it for her, but made sure to cover the light so that it didn't quite look like a real cig. All the while making sure everyone around him could hear the conversation. He says he got approval twice by using that technique, but he made sure not to make a lot of vapor.
I'm not real sure calling it a "smoking cessation" is the best idea; we all know where that can lead. However, if this story is true, it is only a matter of time before airlines are aware of e-cigs and this approach may not be needed any longer. Although, I read an article that the state of Minnesota banned ecigs in bars because it was too close to smoking. So, if this is the case, airlines might just ban them altogether instead of embrassing the technology. Very sad indeed.
EDIT: Looks like my assumption is already coming to realization

Quote from
http://www.e-cig.org/2008/12/17/usin...n-an-airplane/
"After a little bit of research, we have discovered that there are currently three airlines who have added the electronic cigarettes to their lists of unacceptable devices on planes. They all basically state that because the electronic cigarette looks so much like a real cigarette, they are worried that others might think someone is actually smoking and either freak out or start smoking a real cigarette themselves."
SH*T!!!! Stupid f'ers. Pisses me off that they'd rather ban something than actually research it a bit more and actually inform people about it.