Baffled by 31 a. It looks like Air Officer but never heard of it.
A term used to denote the appointment of any RAF officer above the rank of Air Commodore to a position of command 3.7.
An air officer is a Royal Air Force officer of the rank of Air Commodore or higher. Such officers may be termed "officers of air rank". The term is also used by many Commonwealth nations who have a similar rank structure to the RAF.