Hi all, I've been flying quite frequently for the last 5 years and here are my comments on e-cig and air travel:
Security: no problems ever in Canada. going in or out, with e-cigs in carry on luggage. (although I usually try to minimize the qty and size of the stuff)
Planes: allowed in your carry on, checked luggage (make sure you make batteries safe in both, ie disconnect them and cover the poles) For e-liquids... I put them in leak proof bags (ziplocks) same as I would for shampoo.. if it leaks, it just makes a big mess hehehe
Custom going in other countries: you should check on that with the country you are going to... some countries considers those illegal... but then again it is usually not enforced heavily.
Vaping on the plane? Not that I ever have done this myself, um um um, but a friend of a friend of a friend says he goes to the washroom and vape with not problems with the smoke detectors... specially handy in long haul flights.
At the airports: if you have access to lounges, the washrooms are closet type, then no pros. If your going to the public washroom with open stall types... I would not recommend...
PS: after my friend of a friend ect... goes to the plane washroom and comes back all relaxed, make sure he does not forget his e-cig in the seat pocket in front of you before de-planing.... I lost one that way... euu I mean my friend's friends... ect.
Cheers all, and have a great day.