In the past when I've flown, I just packed all my vape gear in my checked bag, but last week I decided to bring a small amount of vape stuff in my carry-on. Before checking my one bag, I approached a TSA rep, showed him my Provari and asked if it was ok to bring through security. He looked at me like he hears the same question all day, and told me "of course".
Once I got to my gate, I noticed a man vaping discreetly near a wall. I then asked the Delta desk rep if vaping was ok and she said "Sure, just not on the plane." I found a seat near a wall with an electrical outlet, charged my phone while happily vaping.
On my return flight from Cincinnati, I had no problems in the security check, but again asked a Delta rep at the gate. He also said it was fine so I repeated what I did in Orlando. Our flight was delayed over an hour because our plane was stuck at another airport, so the ability to vape made the wait so much easier.
I did not vape on the flights because I am so used to not smoking on them, but I loved the fact that, beforehand, I was not having to sit outside or in a smoking room and then board the plane smelling like an ashtray.
Just common sense -- ask politely and accept whatever answer you get gracefully.