Collections (5)1914–1918 / WWI1939-1945 / WWIlIn progress 2×Completed 10×Queued 1×1947-1991 / Cold War EraIdeas 2×Completed 8×On hold 4×Modern / In service Ideas 2×In progress 1×Completed 4×On hold 1×SpaceIn progress 1×Completed 2×On hold 1×