I fly twice a week, mostly domestic some overseas to the UK.
TSA knows all about eCigs, they don't freak out. UK Security out of Heathrow and Birmingham is cool too, So is Charles De Gaulle in Paris, can't speak to other Airports.
Each flight I fly with the following gear:
In laptop bag
2 - Vaporesso Revenger X mods with batteries installed
2 - Vaporesso NRG tanks mounted on the mods, almost full of ejuice
4 - Spare batteries in cases
2 - 60 ml bottles of juice, 2 different flavors*
In carryon suitcase
2 - 100ml (roughly 3.38oz) bottles of ejuice to refill my 60ml bottles*
*without TSA Pre you will need to place these in a 1 quart bag along with your other liquids and gels. So you want be able to take 280ml like I do, just want fit with all your other liquids in a single 1 quart bag.
I once had my tanks swabbed and the swab set off the alarm. Happened once out of 500 or 600 hundred flights, no biggie just extra searches of my bag.
If you have a bottom airflow tank you will need to turn it upside down while the plane climbs to altitude. When it is upside down you don't want the liquid touch the coil where it can pressure out of the airflow. With most tanks this still leaves you plenty to vape if you are going to vape on the plane or between flights on layover. If your tank is top airflow like the Revvo just leave it right side up and as full as you like. I close the airflow on both tanks during the climb. Once at altitude I right my upside down tanks and let them set for 5 minutes to make sure the coil has been rewetted.
Those that get busted stealth vaping on flights are usually turned in by fellow passengers. Some restrooms on planes have vacuum drains. You can identify these by the sound of rushing air in the drain, exhale there. Night flights are better since lights are out. It also helps if your ejuice doesn't have a super strong smell when vaped. Obviously airports and planes are no place to go cloud chasing.
Checked Luggage = Lost Luggage. Never ever check luggage. I can go to the UK for 6 days will my rollerboard carryon.
I have TSA Pre. Worth it if you fly a lot, if you just fly a couple times a year its just annoying to frequent flyers when rookies waste time trying to figure out how to act in the pre check line. They pay for pre check then get to the head of line and act like total morons. They start pulling out 1 quart bags with liquids and gels, take out their laptop, pull their shoes off. I'm the guy behind them telling act like you've been here before.
Hope this helps