Restricted items needing no notification
The following list covers all items that may be carried on British Airways flights but are still restricted to specific limits on quantities or dimensions:
Non-flammable, non-toxic gas cylinders - e.g. for operation of mechanical limbs
Or pack them in your check-in luggage. The hold isn't pressurised.
Monty Dog wrote:
The main reason is that they don't like the noise of leaking gas in the hold - can't tell if its something wrong with the plane or something in someone's luggage.
the hold isn't pressurised
surely you'll do some damge to your tyres if you don't deflate them? as the external pressure drops with altitude the gauge pressure of the tyre increases (internal pressure - air overpressure). if you want to test this idea take an sealed empty bottle in the cabin with you, once you get to a cruising altitude open it and listen to the pressurised air inside escape, the hold isn't pressurised so the effect is greater... (IMHO)