Designed by A. Hessell Tiltman (co-founder of Airspeed), the six-seat Airspeed AS51 Courier was a low wing monoplane, the first British design to be fitted with flaps and undercarriage that retracted into the wings.
The prototype had been specifically built to order for Sir Alan Cobham, aviation pioneer and one of the founding directors of Airspeed Limited, who was looking for an aircraft that had the capabilities of carrying out a long distance flight from the UK to India with the aid of his early air-to-air refuelling techniques. The prototype (G-ABXN) flew for the first time on 10th April 1933, in the hands of RAE Test Pilot George Stainforth. A test flight programme followed, and on successful completion, the aircraft immediately entered into production.
The first production aircraft was delivered on 4th September 1933, to the type's appointed agents, Exchange & Mart Magazine, who demonstrated the aircraft with a flight to Scotland. This, along with other promotional flights, saw a good level of enquiries and potential sales for the new aircraft. In order to bolster interest, the aircraft (G-ACJL) was entered in to the 1934 MacRobertson Air Race (also known as the London to Melbourne Air Race) where it was flown by Sqn Ldr D.E. Stodart and his cousin Sgt. K.G. Stodart. The race featured 41 starters, with the AS51 Courier finishing sixth overall (and third on handicap), with a flying time of 100 hours, and a total elapsed race time of 9 days 18 hours and 11 minutes.
Although intended for private use, small fleets were operated commercially by Portsmouth, Southsea and Isle of Wight Aviation Ltd, North Eastern Airways Ltd and by London Scottish and Provincial Airways Ltd. Due to the aircraft's advanced aerodynamics, two airframes were used purely for aeronautical research, one by the Royal Aircraft Establishment at Farnborough and the other as a development aircraft for the Napier Rapier engine. During the Second World War, surviving Airspeed AS5 Couriers were seconded into the RAF as communications platforms, whilst at the end of hostilities those that were left we used for joyriding flights from Southend Airport.
The final Airspeed AS5 Courier was scrapped in December 1947.