aircraft were assembled at Filton Aerodrome, from assemblies imported via Avonmouth docks. Filton became a major port-of-entry for US casualties after the D-Day landings in June 1944. Most of the casualties were taken to Frenchay Hospital. Aircraft produced at Filton during the war included the Blenheim, Beaufort, Beaufighter and Brigand. Filton Aerodrome was upgraded to a concrete runway during 1941/42. Both a First World War and a Second World War aircraft hangar survived into the 21st century. These have been legally protected and are being refurbished for use by Aerospace Bristol, a new aviation heritage museum that will house the Bristol Aero Collection, alongside a new hangar for Concorde 216. Post war After the Second World War, the concrete runway at Filton Aerodrome was extended westwards by John Laing & Son to enable the huge Bristol Brabazon airliner to take off safely. This extension required demolition of the hamlet of Charlton; it also severed the pre-war Filton bypass. The three-bay Brabazon Hangar was built in the late 1940s under the direction of T. P. O'Sullivan. The hangar doors and the railway level crossing for the aircraft were the largest in the world at the time. After a worker was crushed and killed while taking a sleep in one of the folds of the hangar doors, a siren was installed to warn employees when the doors were being operated. During the late 1940s and early 1950s, BAC branched out into the development and production of pre-fabricated buildings, plastics, helicopters, guided weapons, luxury cars, gas turbines and ramjet motors. The Bristol Britannia (Whispering Giant) airliner and Bristol Freighter were produced. In 1948, 501 Squadron was equipped with De Havilland Vampire jets. These were a common sight in the skies around Filton in the early to mid-1950s. 501 was disbanded on 3 February 1957. As a protest, one of the pilots flew his aircraft under the Clifton Suspension Bridge, but he crashed into a hillside on the Leigh Woods side of the Avon Gorge, near Sea Mills, Bristol, and was killed. During the late 1940s and early 1950, British Overseas Airways Corporation (BOAC) flew their Lockheed Constellations and Boeing Stratocruisers into Filton to be serviced in the newly completed Brabazon Hangar, then the largest hangar in the world. Maintenance flights to Filton ceased when suitable hangars were completed at London Heathrow Airport. In 1954, BAC opened a technical college for apprentices and trainees