[5] In 1928, he joined the de Havilland company as a premium apprentice, working in the engineering department, with his last two years spent in the drawing office.

[5] Alongside his apprenticeship, he learnt to fly at the Royal Air Force Reserve School located on de Havilland's Stag Lane aerodrome.

[5] When his apprenticeship ended in 1932, he left to join the Aircraft Operating Company as a pilot carrying out air survey work in South Africa.

[3] On 11 April 1939, de Havilland and John Cunningham narrowly escaped with their lives during a test of a Moth Minor's spin response.

[5][6] When the UK entered the Second World War, de Havilland were manufacturing Oxfords and Flamingos, which Geoffrey was testing.

On another occasion, a Hurricane's oxygen bottle contained only compressed air, causing Geoffrey to blame its effects on him on the previous night's party.

Like the original prototype, the aircraft had been manufactured in the dispersal factory at Salisbury Hall, but to save the six weeks that would have been spent in transporting and rebuilding the airframe at Hatfield, Geoffrey used adjacent fields as a runway by having bridges built over ditches to give him a 450-yard (410 m) run for take-off, and then flew the fighter to Hatfield.

[5] Following an informal approach by Henry Tizard in January 1941,[citation needed] the de Havilland company began developing an experimental jet fighter that would later become the DH.100 Vampire.

His body was found on the mud flats at Whitstable, his parachute pull ring untouched;[8] he suffered a broken neck, the result of the aircraft having undergone severe and violent longitudinal oscillations prior to break-up, which caused de Havilland's head to strike the cockpit canopy with great force.