As a young man he fought in the Second Boer War, before becoming a pioneering aeroplane designer in the early years of the 20th century. Dunne worked on automatically stable aircraft, many of which were of tailless swept wing design, to achieve the first certified stable aircraft. He later developed a new approach to dry fly fishing before turning to speculative philosophy, where he achieved some prominence and literary influence through his "serialism" theory on the nature of time and consciousness, explained in his book An Experiment with Time.