The De Havilland Aircraft Company was formed as a result of the of the sale of Airco, where Geoffrey De Havilland had been chief designer, to BSA. Due to the financial difficulty that Airco was in when it became part of BSA the decision was taken to liquidate it and the company’s assets were placed for sale. They were bought by de Havilland, with the help of an investment by George Holt Thomas, who was able to use them to found his own company at the Stag Lane Aerodrome, near Edgware. Initially work was focused on maintaining and providing spares for surplus DH.4 and DH.9 aircraft that had been produced by Airco and were being operated by various civil organisations. Beyond this the company focused on the growing civilian market by continuing with the development of the DH.18 airliner, which had also begun by Airco.

During 1924 Alan Samuel Butler became chairman of the De Havilland Aircraft Company Ltd following a large investment that had result from an aircraft the company had built for him. At this time, the company was producing DH.9 and DH.9A aircraft as well as experimental designs for the Air Ministry and the DH.50 four passenger aircraft. It was also work on designs for what would become the DH.54.

On 22nd February 1925 the first flight of the DH.60 Cirrus Moth, a small two seater biplane, was undertaken. This design would lead to a series of successful aircraft that were popular with private aviators and the Air Ministry. The success of this design also led to the development by De Havilland of their own engine design, as the war surplus designs they had been making use of were running out. This would become the Gipsy and was used to produce the DH.60 Gipsy Moth. The new engine development also led to the establishment of the company’s engine division in 1926.

During March 1928, a new subsidiary was formed known as the De Havilland Aircraft of Canada Ltd. This was based in Toronto and built Moth aircraft as well trained Canadian aircrew. Soon after the De Havilland Aircraft Pty Ltd was established in Melbourne. In 1929 the De Havilland Aircraft Company was listed as a public company, with de Havilland himself continued in his role as technical director. At this time, the company was concentrating on the production of single and two seat biplanes, many of which were continuations of the work of Airco but which also included the Gypsy Moth, one of which was flown by Amy Johnson to Australia in 1930. They had already expanded production to include several models of airliner which included the DH84 Dragon, DH84B Dragon Express and DH89 Dragon Rapide. It had also established additional overseas facilities, beyond those in Australia and Canada, in India, New Zealand, South Africa and the United States of America.

In 1931 the Gipsy Moth was redesigned to meet an RAF specification for a training aircraft. This was the DH.82 Tiger Moth. De Havilland also designed a number of aircraft with enclosed cockpits as both he and his wife were tired of travelling in open designs.

In 1932 the De Havilland Aircraft Company moved to Hatfield, although the Stag Lane site was retained for the production of aircraft engines, and in 1935 De Havilland Propellers was established as a subsidiary. This was established to construct Hamilton Standard variable pitch propellers under licence. The production of these would be undertaken at a newly established facility in Lostock. Also, during the late 1930s the company would work on the development and production of the Albatross and Flamingo airliners. Production of these designs would be interrupted by the outbreak of the Second World War, although the limited number produced would find use in the Royal Air Force and BAOC.

During the war, de Havilland undertook a great deal of work in repairing battle damaged Hurricanes and also produced 150 Airspeed Oxfords. In additions to this October 1939 saw the beginning of design work on an unarmed bomber that would subcontract work to furniture and coachbuilding companies, which would otherwise have a limited role in the war effort. On 3rd October 1940, the Hatfield site suffered its only direct damage of the war when four bombs hit one of the workshops killing 21 and injuring a further 70. In response the work undertaken here was later dispersed. Later in 1940 the Mosquito undertook its first flight and would later enter service with the RAF in July 1941.

Also at this time, the company developed both the Goblin jet engine and the Vampire which it was used in. This would undertake its first flight on 20th September 1943 and achieved a speed of 500mph in 1944, but production would not begin until after the end of the conflict. In addition to this it would be the first jet powered aircraft to land on an aircraft carrier in December 1945 when Lt Cdr Eric ‘Winkle’ Brown landed one on HMS Ocean.

De Havilland’s development of civilian airliners would also continue during this period. In late 1944 it would begin design work on a small aircraft to meet the type 5B specification that had resulted from the Brabazon Committee. This would become the Dove, which would first fly on 25th September 1945, on the 25th anniversary of the company, and would be later developed into the larger Heron. Both of these would be constructed at a new site, acquired in 1948, at Hawarden Airport also known as Broughton.

During 1946 the company also undertook work aimed at breaking the sound barrier. In order to do this a new design, the tailless DH.108 Swallow, was produced and this was first flown on 15th May 1946. Although it would be the first aircraft outside North America to fly supersonic, achieving this on 7th September 1948, it only achieved this after one of the aircraft broke up in flight on 26th September 1946 killing the company’s chief test pilot, Geoffrey De Havilland Junior.

On 27th July 1949 the first flight of the jet powered Comet airliner was undertaken. This had been initially developed to meet the type IV specification from the Brabazon Committee, for a high speed transatlantic mail plane, but had been changed to a passenger aircraft. The design entered service on 2nd May 1952 as the world first commercial jet airliner. 1949 also saw the first flight of the Venom fighter, which was based on the previous Vampire design but with a more powerful engine.

In 1951 the De Havilland Aircraft Company the first prototype DH.110 Vixen was completed. This was a larger RADAR equipped fighter design that was developed for use by both the Fleet Air Arm and the Royal Airforce. On 6th September 1952 it would be demonstrated at the Farnborough Air Show. After breaking the sound barrier it turned towards the crowd but broke up during the maneuverer killing both the aircrew aboard and 29 members of the public on the ground. 60 more would be injured and following the accident stricter regulations relating to aerial displays were introduced.

The company would also suffer further losses during the early 1950s when three Comets would break up during flight. This would lead to a series of inquiries into these losses, as well as the grounding of all the Comets then in service. Although the design would be improved to produce the Comet 4, by the time this was introduced other designs had been introduced and orders were severely limited.

During 1955 the company underwent a major reorganisation. The De Havilland Aircraft Company, De Havilland Engine Company and De Havilland Propellers Ltd all became subsidiaries of De Havilland Holdings Ltd.

In the late 1950s the company would be involved in the development of the Blue Streak rocket and also formed a joint venture with Hunting Aircraft and Fairey Aviation in order to produce the DH.121 Trident, under the name Airco. This would be the last airliner developed independently by the De Havilland Company as in 1960 it would be acquired by Hawker Siddeley to form part of their aviation division. Although it would continue to operate under its own name for a short period, during which it acquired S.G. Brown from the Admiralty, this would only last until 1963 when Hawker Siddeley took the decision to discontinue the use of the various names it was using in favour of a single Hawker Siddeley brand.