You may or may not have heard a few of the stories out there about some people vaping on planes. You might have even done this yourself and gotten away with it, or had a friend do so and tell you how they did. Do not, under any circumstance, vape on a plane! Remember this simple rhyme; if you're on the ground, eLiquid vaping is sound, but if you vape on a plane, you're in for some pain.
You might think that you're "stealth vaping" but people around you do know and the flight attendants are pretty good at catching it. It used to be up the flight crew to decide whether vaping on their plane required law enforcement action. New rules absolutely require law enforcement response for any smoking/vaping on an airplane.
If you get caught in your seat it's one thing, but if you vape in the lavatory and set off the smoke detector things will not end well for you. You will most certainly be met by law enforcement upon landing. It's not only illegal, but planes are considered federal territory, so it's extra not good. Keep your eLiquids safely restrained until you exit the plane and terminal!
Until we can get some sensible regulation in this whole vape world, it's always best to play it safe. Someday we may have sane regulation and then we can take the debate to the planes, and maybe then you can vape on a plane like you can use your cellular devices nowadays.