Elliotts of Newbury were experienced wartime glider manufacturers but at the end of World War II decided to venture into the design and production of powered aircraft. The result was the EoN A.P.4 (more commonly called the Newbury Eon), a wooden four-seat monoplane with a fixed tricycle landing gear. The design had been carried out by Aviation and Engineering Products Ltd of Feltham, Middlesex. The prototype Eon 1 registered G-AKBC powered by a 100 hp (75 kW) Blackburn Cirrus engine first flew at Welford, Berkshire, on 8 August 1947. After initial testing was completed, the prototype was modified to reflect the planned production version. The main changes were a new engine, a de Havilland Gipsy Major of 145 hp (108 kW), and a lengthened nose-wheel leg. The modified aircraft was redesignated the Eon 2.
The company decided not enter production and it continued as a glider manufacturer. The sole completed Eon aircraft was used as a glider-tug to demonstrate the company’s gliders. The aircraft met its end at Lympne airfield, Kent, on 14 April 1950, when, with a glider attached the pilot started the aircraft by swinging the propeller with the aircraft's wheels not secured by chocks. The engine started, and the craft moved forward; the pilotless aircraft and the glider were damaged as the aircraft passed through a boundary hedge. The glider pilot had also abandoned his cockpit when he realised what was happening.