Hi Pieter,

Regarding the security at airports: I fly at least 2-3 times per week and can tell you that if you have your bottle empty when it is time to go through the checkpoint you will be fine. But, if you have it full - they won't allow it. If you are going to use one that isn't disposable and you need water every couple of minutes - I would take your empty nondisposable one AND a full disposable one. Drink the disposable until right at the point you go through the machines in security - you can keep it until you pass through the metal detectors. After that - take your nondisposable and find the nearest water fountain to fill. That is your best bet. Anything with liquid in it that holds over 3.4 ounces will be tossed by security - even if it is only partially full. I see tons of toothpaste tubes that are the full size but only have a little in there - thrown out all the time.