The Auster was a twice-removed development of an American Taylorcraft design of civilian aircraft, the Model A. The Model A had to be redesigned in Britain to meet more stringent Civil Aviation standards and was named the Taylorcraft Plus C. After the start of the Second World War, the company developed the model further as an Air Observation Post (AOP)—flown by officers of the Royal Artillery and used for directing artillery fire of British Army Royal Artillery units.