Originally Posted by Boom Master
It would be prudent to fly the air tanks EMPTY. The pressure differential is a lot MORE at 12000 feet.
At STP air pressure is 14.7psi, with a pressure differential on a full fill being up to 4485.3 psi. Even if the cargo compartment were somehow a complete vacuum that still only adjusts the pressure differential to 4500psi which is what the container is rated for in the first place.
Now, it may be prudent to empty the air tank. And on a commercial flight the regulator is required to be removed before the security checkpoint. But this is more for other safety-related reasons - ensuring liquids aren't being stored, ensuring hazardous gasses aren't being stored, that sort of thing.