By 1921, enough experience had been gained with operation of the de Havilland DH.18 to realise that aircraft needed to be more efficient to improve the economics of air travel.

de Havilland therefore built the ten-passenger DH.29 monoplane, while starting work on the design of the DH.32, a biplane of similar size and capacity to the eight-passenger DH.18, but with a less powerful but more economical Rolls-Royce Eagle engine.

[1][2] Consultation with potential users resulted in work on the DH.29 and DH.32 being stopped and a new airliner, the DH.34 biplane designed, with a similar fuselage to the DH.29, accommodating nine passengers.

[1] Unusually, the design of the aircraft allowed an entire spare engine to be carried on board across the rear of the passenger cabin.

[8] When Imperial Airways was formed on 1 April 1924, by the merger of Daimler Airway, Instone Air Line, Handley Page Transport and the British Marine Air Navigation Company, it inherited six D.H.34s, retaining the type in service until March 1926, when it retired the DH.34, abandoning single-engined aircraft in favour of multi-engined aircraft.