After engineering school, his first interest was in automotive engineering, building cars and motorcycles. He married in 1907 and almost immediately embarked on the career of designing, building and flying aircraft to which he devoted the rest of his life.
His first plane took two years to build and he crashed it during its first very short flight near Litchfield in Hampshire. A memorial today marks the place. Subsequent designs were more successful.
He joined HM Balloon Factory at Farnborough, which was to become the Royal Aircraft Factory as it realised the importance of planes and shifted some attention away from balloons.
Employed during World War I by Airco, he designed many planes used by the Royal Flying Corps during that period.
After the war, de Havilland bought Airco, renaming it De Havilland Aircraft Company. One of his roles was as test pilot for the company's aircraft, in all of which he liked to fly.
The company's planes, particularly the Mosquito played a formidable role in World War II, and de Havilland was knighted in 1944.
He controlled the company until it merged into the Hawker Siddeley Company after disastrous problems killed passengers aboard its cutting-edge Comet jet airliner in the mid 1950's.
Two of de Havilland's three sons died as test pilots in de Havilland aircraft.