In the RAF, the commissioned ranks are Pilot Officer through to Marshal of the Royal Air Force. They are generally referred to as 'officers'. In the RAF, a commissioned officer is a member of the Service who derives authority directly from a sovereign power (i.e. the Monarchy), and as such holds a commission from that power. Any officer (and all non-commissioned ranks) address a senior officer as "Sir" or "Ma'am".
NCOs are enlisted members of the RAF who have been delegated leadership or command authority by a commissioned officer. They are the junior management of the Service. Experienced NCOs are a very important part of many armed forces; in many cases NCOs are credited as being the metaphorical "backbone" of their Service, and of their individual units.
Warrant Officers (WOs) are often included in the SNCO category, but actually form a separate class of their own. A Warrant Officer will have many years experience and is respected by both rank structures. Warrant Officers are addressed as "Mister" (or "Mrs", "Ms" or "Miss" for female Warrant Officers) by commissioned officers (and as "Sir" or "Ma'am" by everyone else). SNCOs and WOs have their own messes, whereas JNCOs live and eat with the junior ranks.
