in the US, you're not allowed to take containers of liquid larger than three fluid ounces through airport security.
I wonder what they would do if you took a half-litre water bottle full of ice
@Felthry or wait they only allow it if used to keep medical supplies or food cold. lol. rules asking to be bent
@Felthry they allow it, because things that can explode only freeze at around -60 or lower, so you'd have to have a really good thermos for it to be an explosive.
@Felthry they actually allow it believe it or not