teknitroxdiver
Contributor
Transportation of compressed gas cylinders is regulated by the Interstate Commerce Committee. For transport by air they must be empty, and to prove they are empty, the valves must be removed. I will search my bookshelf to see if I have an exact reference.
Still, no. The ICC covers, as the name implies, commerce. Think about it...if ICC rules applied to private, non-commerce operations, you would be required to secure your tanks in your car upright and with proper straps, just like the Airgas truck does. A private aircraft is no different than your pickup truck. If it's not in the FARs, and part 91 to be specific, it doesn't matter for a private flight.