This is a warning if you have one that travel is not as straight forward as the vendors would have you believe.
I had my Snowpulse carbon cylinder stopped in Tokyo on the way to the Hokkaido tour. The ANA customer services made huge efforts over the last week to get it returned to me, but were unable to do so and have now agreed to pay the cost of a replacement (list price £170). Currently, I would recommend not travelling to Japan with one unless you are prepared to invest several weeks before getting pre clearance through your airline.
There appear to be various idiosyncrasies to the policies in different places e.g. I understand that Canada require that the rucksack is checked in with the cylinder. My understanding is that despite the rules below, many do not accept the cylinders in hand luggage.
For your information, I have attached the IATA rules and this is the link to the Civil Aviation Rules
https://www.caa.co.uk/Passengers/Before-you-fly/Baggage/Items-that-are-allowed-in-baggage/#4294967551-accordioncollapse-16
You will see that the CAA requires that you obtain approval from the airline. The EasyJet website seems to quote IATA but does not mention contacting them. I have done this anyway.
Discussions of the issues can be found at
http://www.powpowpow.org/an-open-letter-to-easyjet/
http://snowheads.com/ski-forum/viewtopic.php?t=72233
John Russell