[1] Detailed design of the new aircraft was the responsibility of John Kenworthy, who drew up plans for a two-bay biplane with wings similar to those of the B.E.2, but more heavily staggered.

Testing was sufficiently successful for de Havilland to take several passengers up in the B.E.3 later that day, and the aircraft was delivered to the Royal Flying Corps (RFC) on 13 May 1912.

[6] Kenworthy modified the design to allow fitting of a more powerful (140 hp (104 kW)) two-row Gnome engine, which was built as the B.E.7, flying for the first time on 28 February 1913.

[6] The B.E.7 was also taken on charge by the Central Flying School, serving until November 1913, at which time its engine bearers were found to be damaged by the heat of its exhaust fumes.

[7] 204 crashed on Salisbury Plain on 11 March 1914 when its rudder failed, possibly due to metal fatigue, killing its crew of two.