Following the war, De Havilland turned his focus to commercial jets, developing the Comet and the Ghost jet engine. The de Havilland Ghost (originally Halford H-2) was the de Havilland Engine Company's second turbojet engine design to enter production and the world's first gas turbine engine to enter airline service.A scaled-up development of the Goblin, the Ghost powered the de Havilland Venom, de Havilland Comet and SAAB 29 Tunnan. The De Havilland Comet was the World’s first pressurised commercial jet airliner and it was the source of enormous national pride. Entering service at the end of the Second World War, the Hornet equipped postwar RAF Fighter Command day fighter units in the UK and was later used successfully as a strike fighter in Malaya. After its July 1949 test flight, the Comet … Its introduction into BOAC service in May 1952 was greeted as the dawning of a new age in passenger travel. A tiszta vonalvezetésű repülőgép négy de Havilland Ghost gázturbinás sugárhajtóműve a szárnytőben foglalt helyet, nagy trapéz alakú szárnnyal és túlnyomásos törzzsel készült. A de Havilland DH 106 Comet az első sorozatban gyártott sugárhajtású utasszállító repülőgép volt. While the prototype was being built, de Havilland bought Halford's firm and reformed it as the de Havilland Engine Company, renaming the H-1 and H-2 as the Goblin and Ghost respectively. A gép prototípusa 1949. július 27-én szállt fel először.

There he designed the famous de Havilland Gipsy air-cooled inline engines, copying the success of the Cirrus Engine company in the general aviation role. The de Havilland DH.103 Hornet was a piston engine fighter that further exploited the wooden construction techniques pioneered by de Havilland's classic Mosquito.