""Prince Charles becomes a Field Marshal, Admiral of the Fleet and Marshal of the Royal Air Force.
Well there you go. Anyone here like to tell us how he "earned" all this? Heheh!""
Those are purely honorary and ceremonial titles. He'd get short shrift if he tried to issue orders. Militarily he holds only such reserve rank as he may have earned in service.
The level of ignorance in some of these responses is abysmal.