I've posted my experiences elsewhere just not so good at getting the links to work in rply. Basically, I put tanks with juice in them and juice bottles in their own little baggie, the tanks will leak a little bit so don't want that on your toiletries or clothes, I put these in my 1 qt. carry on liquids bag. batteries, cartos, chargers I leave in my laptop bag. My travels generally don't require me to check bags, but if I were to check bags, I'd still take my gear on board since I don't want it to get lost. I've had no issues after at least a dozen trips thru TSA screening in the past 4 months. One time I was questioned about my tanks and I think that's cuz the drip tips were attached. I told them honestly that it's ecig and they were fine with that.
On the plane, I'm sticking with the lavatory for a quick vape on a long flight. Today I sat next to a pilot that was going home and asked him about it and he said that "generally" no, it's not allowed but he said that sometimes flight attendants don't say anything if you're discreet. Mostly, the concern is just that people don't know about them and may complain and the crew doesn't want to have to deal with any altercations. So it's easier to just not openly allow them.