Hi team! Because it is such a hot topic of with this hobby, I wanted to share my recent experience getting through international security at LAX on my way to Barcelona. I have another flight from BCN to London as well in a few days, I have some insight there as well.
The most important detail here i think is that my battery was completely disconnected from everything and was in a place in my carry-on suitcase where the TSA could easily handle it and also see that all of the connection points where secured from short circuit. I briefly explained that the nominal voltage is 3.7 volts and the capacity of each cell is 1000 mah for a total of 148 watt hours. I offered to explain every part of the entire set-up if they needed more information. I made sure to be as friendly and open as possible, which i think helped. I also called my airlines customer service before hand just to be on the record with them that I was going to bring the battery and that I discussed the limits with them.
I requested before they handled the battery that they please be careful with my VESC (@chaka) and with the BMS attached to the outside of my battery (@barajabali i still owe you that 2a charger, im so lazy!). I explained that if either of these pieces broke, I might as well just take the battery home. I should also mention that I live just 20 minutes (sometimes) from LAX in Santa Monica, I showed up 8 hours before my flight just in case I needed to take the battery back home. They wiped down and tested my entire suitcase for explosives for maybe 10 minutes, inspected all of my tools, then told me I was good to go!
I also want to mention that I was already 100% prepared for them to say no. This took a lot of prep because I tend to get very emotional and didnt want to risk a bad reaction if they rejected the battery and made my trip less fun. I wanted to be as friendly and forgettable as possible.
I made it through with no issues on airline one from LAX to Barca. Maybe a small detail to note is that I was only comfortable with this because all of my tickets are first class and guarantee that I will not have to check my bag if space runs out in economy. Batteries need to be in cabin and also I want to know immediately if something happened to my bag. Id probably have anxiety attack if I had to check my carryon because of overhead space running out.
Now for flight number 2 from Barca to London. This flight has not happened yet, but its important to note that I talked to customer service about bring the battery asked to get an ok-go from someone so that there could be a point of contact from the airlines safety department should TSA try to reject the board while Im overseas (id just send it to @Menjos as a thank you present for showing me around and showing me the best healthy bar in Barceloneta!) because shipping to the US is insane and I could just order a new battery for not too much more. I blotted out the email address for the airline because I want to encourage everybody to just call and open up a friendly relationship with the CSR and safety team. They will give you the best information as long as youre cool to them. It is not hard to be decent with them and it was a very fast process to get this approval.
Im attaching pics of the email I sent, as well as my approved tools and also a visual representation of what this TSA agent deemed okay and not super sketchy. I am no professional wire worker, so I cleaned up the look as much as I could the night before my flight. I would consider this to be the lower limit standard for how sketchy it should look. Please dont have ridiculous wires everywhere!
Thanks team, I hope this encourages more people to pursue traveling with their eskate. It has totally made my trip so far!
Also, dont ask questions about the 1000 mah capacity of my cells 
