Second in the trio of British four-engined bombers, the Handley Page Halifax was also the second most important bomber in the RAF arsenal during the allied Strategic Bomber Offensive. It was originally designed to carry two Rolls-Royce Vulture engines but was later switched towards four Merlins (and later, Hercules) thus forming two separate families of aircraft. Halifaxes first arrived for squadron use in late 1940 and made their first bombing run on March 1941. With their considerable bomb load and range as well as advanced technology like H2S ground-mapping radar, Halifaxes were a formidable addition to Bomber Command until the end of the war where they flew the incredible amount of 82,072 missions and dropped 227,610 tons of bombs over occupied Europe. Production of the Halifax ended in 1946 and they continued to be used post-war for various non-combat duties, notable of which was the parachuting of agents and supplies for various resistance movements in Europe. Besides the UK, other Allied users included Australia, Canada, and New Zealand. They were retired from RAF service only until 1952.

First flown on 25 October 1939, initial production variant Mk. Is featured a two-gun nose turret but lacked a rotating dorsal turret. Subsequent variants like the Mk. II and sub-variants added more defensive armament and more powerful engines. The most widely produced version of the Halifax was the Mk. III with Hercules XVI radial engines and an increased wing span. This was followed by the Mk. V with a Bolton Paul dorsal turret and the Mk. VI designed for operations in the Far East (the only British heavy bomber to serve in that theater). Wartime variants went up to the Mk. VIII and were also used by Coastal Command and as transports and glider tugs. Among these specialized aircraft were the C.VIII transport and A.IX paratroop carrier.