Now the American Air Museum at IWM Duxford has been granted Grade II-listed status by English Heritage. The American Air Museum at Duxford. During the Second World War, Duxford was both an RAF and a United States Army Air Force station, playing an important role in the Battle of Britain. Renato Niemis’s memorial sculpture Counting the Cost, part of the museum, was also recognised. It is made up of 52 large glass panels engraved with silhouettes of the 7,031 American aircraft lost on operations during World War II.