Stealth technology, especially in bombers, has a long history. During World War I, both sides made serious efforts to camouflage aircraft and muffle their engines. The Germans experimented extensively with a celluloid-like material called Cellon; they tried this coating on almost two dozen different aircraft in hopes of reducing visibility. As it turned out, Cellon was a failure at reducing visibility; instead it made aircraft quite bright and extremely flammable.
