I'm going through this right now myself in preparation for a charter
. Take a look at the website(s) for each airline you'll be flying on. They all have slightly different policies. For example:
United Airlines says this:
We accept one carbon dioxide-powered inflatable
life jacket as a checked or carry-on bag. You must pack carbon dioxide cartridges as checked bags.
We’ll also accept up to two small nonflammable gas cylinders fitted into the life jacket and up to two small spare cartridges.
If the life jacket has flares or flare guns
attached to it, you must remove them or we won’t accept the jacket.
If you have questions or concerns about a specific item, please contact United Cargo.
Lufthansa Airlines says this:
Small gas cartridges containing carbon dioxide or other gas listed in Hazard Division 2.2, e.g. suitable for self-inflating life jackets, espuma bottles or for inflating tyres, plus up to two spare cartridges.
Checked baggage: yes
Carry-on baggage: yes
Carrier’s approval required: yes (1)
Rules for life jackets and similar safety
maximum of one item per passenger
must be packed in such a way that accidental activation is impossible
limited to carbon dioxide/other appropriate gas in Hazard Division 2.2 without a subsidiary risk
the cartridges must be for inflating the life-saving device
for other devices (apart from life jackets): no more than four cartridges up to 50 ml.
In the case of carbon dioxide, a gas cartridge with a water
capacity of 50 ml is equivalent to a 28 g cartridge.
(1) = This permission is not given in writing. It is given upon request and confirmed verbally at the Service
Center or, at the latest, when checking in at the airport