Aeronautical progress during the 1914-18 war, meant that the aeroplane had graduated from a fair-weather vehicle for the few to an everyday vehicle for the many. With this in mind, in 1924 the Air Ministry held a competition with the object of discovering a light two-seat machine, of low power and economical operation, suitable for the owner-pilot.

The immediate result of this competition was disappointing, because all the entries proved to be underpowered, but the long-term effect was to interest designers in light aeroplane problems and, eventually, to lead to a number of highly successful two-seat private-owner types.

These machines were mainly of the tandem open-cockpit variety, similar in arrangement to the early Hawk monoplanes, and it was not until 1936 that the class neared an ideal in the Miles Whitney Straight side-by-side cabin monoplane. This aeroplane was the result of collaboration between the wealthy aviation enthusiast Mr. Whitney Straight, who then operated a series of flying clubs in various parts of the country, and Mr. Miles, both having almost identical ideas on the form of a modern light aeroplane.

The prototype Whitney Straight (G-AECT) first flown on 14th May 1936 and its all-round good qualities exceeded expectations, comfortable and easy to fly, with a top speed of 145 mph. and a fuel consumption of over 20 miles to the gallon. Immediate production followed the successful flight tests, and 50 M.11A, M.11B and M.11C aircraft were sold in almost every part of the world over the next two years. A number of these were used for experimental purposes, including the testing of various engines and, on the prototype, of auxiliary aerofoil flaps, the data gained proving beneficial to later Miles aircraft. A later model, known as the M.11 C, was fitted with the Gipsy Major Series II engine and a variable pitch airscrew, this combination giving a remarkable take-off and climb performance.

Perhaps one of the finest demonstrations of the all-round handling qualities of the machine was provided by the result of the 1937 King's Cup Air Race, in which General Lewin, then aged sixty-three, flew his own Whitney Straight into second place after a very close contest.

On the outbreak of war, in 1939, most of the Whitney Straights in Britain were requisitioned for R.A.F. communication duties, including 23 for the RAF (21 in the UK and two in India), and three for the Royal New Zealand Air Force. Many were still giving good and faithful service after five arduous years.

An improved model of the M.11 was developed with three-seat accommodation and flown as the M.17 Monarch on 21st February 1938.

Crew:        two
Length:      25 ft (7.6 m)
Wingspan:   35 ft 8 in (10.9 m)
Height:       6 ft 6 in (2.0 m)
Wing area:  178 ft² (16.5 m²)
Empty:       1,250 lb (570 kg)
Loaded:     2,000 lb (900 kg)
Powerplant: 1 x de Havilland Gipsy Major I (The de Havilland gipsy major was a 4-cylinder, air-cooled, inline engine used in a variety of light aircraft...)