It is a violation of Federal Aviation Regulations as well as IATA (international) regulations to carry compressed flammable gas containers on passenger aircraft. Examples include propane tanks, iso/propane/butane fuel cartridges for stoves and lanterns and the small butane cartridges for Thermacells and hair curling irons. Incidentally, the curling iron butane cartridges work in the thermacell and are way cheaper. Some airlines have instituted more stringent regulations that say they will only allow new, unused liquid fuel camping stoves and fuel bottles in checked luggage. You need to check with the airline or airlines (code share agreements) you are flying. Some bag screeners are better than others. I was once paged in the Air New Zealand boarding area, marched to the baggage area and told to dig out a small alcohol stove the diameter of a pop can so that the screener could smell that I washed out all traces of flammable liquid (I had). I am not sure if you can ship gas cartridges on cargo aircraft but if allowed they would go as HAZMAT and the charges would be prohibitive. Butane lighters are not allowed in checked baggage but you are allowed to carry one small butane lighter on your person.
Now the reasoning behind the FAR. When the aircraft is at 35,000 feet the cabin is at 6,000 feet. At 40,000 feet (an altitude I have had to climb to between Anchorage and Fairbanks to avoid thunderstorms in the summer) the cabin was at 8,000 feet. I have had gas cartridges leak in my backpack while hiking at altitudes lower than 6,000 feet. The real danger occurs if the aircraft has pressurization problems which I have experienced twice (DC-10, B-727). Once we caught the cabin and did not deploy the masks but the other time we could not descend below 10,000 feet until clear of terrain (much terrain in Alaska?) so the masks were deployed. Most aircraft have oxygen generators in the panel above passenger seats that generate high heat when making oxygen. Remember Value Jet over the Everglades?
There are similar problems in the cargo hold. No o2 generators but numerous sources of electrical shorts to ignite a flammable gas mixture if a gas cartridge valve leaks. Obviously someone sneaking a gas cartridge in baggage would always remove the lithium batteries in their luggage. Remember TWA 800?
So if you are contemplating sneaking a gas cartridge aboard a passenger plane you are not flying solo, please have the decency bring your kids along. If the plane blows up there is better chance that the stupid gene you are carrying will be more likely to be stamped out.
