Columbia subject headings:
United States. Army Air Forces--Aviation--Safety measures--History.
United States. Army Air Forces--Equipment--History.
Harvard subject headings:
United States. Army Air Forces--Aviation--Safety measures--History.
United States. Army Air Forces--Equipment--History.
World War, 1914-1918--Equipment and supplies
World War, 1939-1945--Equipment and supplies.
Princeton subject headings:
United States. Army Air Forces--Aviation--Safety measures--History.
United States. Army Air Forces--Equipment--History.