It is equivalent to warrant officer in other trades, and is effectively the highest non-commissioned aircrew rank.
People holding this rank used to be referred to by different titles depending on their specialisation: This rank is the sole survivor of a system of separate ranks for aircrew which existed between 1 July 1946 and 1950 (another system for technical staff existed between 1950 and 1964).
The badge of rank is a small version of the Royal Arms (as worn by a warrant officer) with an eagle below, all surrounded by a wreath.
Master aircrew receive a warrant signed by the Secretary of State for Defence.
The Royal New Zealand Air Force used the rank until June 2007 when the Master Aircrew rank reverted to Warrant Officer.