Security and luggage. In most countries a therapy device travels as a medical device and does not count against your hand-luggage allowance, and it should travel in the cabin — not in the hold, where it can be crushed or frozen. Expect it to be taken out of the bag and screened separately, sometimes swabbed. A printed line from your supplier or a copy of the prescription is not usually required and is worth carrying anyway, because it converts a five-minute conversation into a ten-second one. Rules vary by country and change — check your airline and your destination rather than a forum post from last year. Water. Empty the humidifier chamber before you fly; carry it dry. Distilled water is hard to find in some countries — bottled still water is what most people fall back on, and a few dry nights are not a catastrophe. Do not fill the chamber from a tap you would not drink from. Hotels. Ask for a room with a socket near the bed; it is a normal request and nobody thinks anything of it. Take a short extension lead if you want to stop thinking about it entirely. Add what you have learned — especially about countries with unusual rules. This thread is more useful the more of you edit it by replying to it.