Quick rules for flying with co2 cartridges in carry-on and checked baggage. Verdicts and conditions across the major aviation regions below.
Life jacket CO2 cartridges (self-inflating): max 2 per life vest + 2 spares per passenger, allowed in both. Small CO2 cartridges for personal use (SodaStream, paintball, bike inflators) generally restricted — must be small (<28g each), max 4 per passenger, and many airlines require checked only. Large CO2 cylinders / scuba tanks banned. Always confirm with your airline.
Life vest cartridges: 2 + 2 spares allowed. SodaStream and similar: pressurized gas containers generally banned; some airlines allow small (<28g) cartridges in checked only. Better to buy CO2 at destination.
Life vest CO2 allowed per IATA rules. SodaStream-type pressurized cartridges generally restricted to checked baggage if allowed at all. Verify with airline.