Before D-Day, US-manufactured 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.