As this thread is discussing many aspects of honorary ranks in the RAF, may be allowed to invade to ask a question which I have wondered about for many years.
A friend of mine, sadly no longer with us, was a medical doctor and held a fairly high position in the Biological Warfare Establishment at Porton. As such he traveled extensively and, whenever possible, he had to use RAF transport for security reasons. As a civil servant he told me that he held an honorary rank of Air Commodore and often speculated that, in the unlikely event of a diversion when civilian passengers had to be put up overnight, that he might have to take responsibility for them as the senior officer on board. Presumably in the air, the captain would be in command.
Was this just conjecture on his part or could it have happened?