early 1980s', as part of training exercise, RAF jets were hunting for a blimp flying over London on a dark and rainy night. Couldn't find it. radar couldn't see it. Blimp sailed at about 1,000', directly OVER Buckingham Palace.
It's really pretty simple. the blimp is made of fabric covered with urethane. radar passes through it, just as it passes through a radome. (radome.hold that thought)
late 1980's, Lockheed Martin builds "Sea Shadow".......built much like an F-117, on a SWATH hull. Now, it´s still classified, but we can assume that it was constructed much like an F-117 as well, that is...with lots of carbon fiber, some interior faceting that causes electromagnetic waves to be absorbed or reflected in directions that minimize detection. Fine. nice stealty craft, as ship go. Ah....but what if it couldFLY? No wake. No sonar signature at all. Very little infra-red signature. built in the same manner, so still minimal radar detectable. bury the engines deep inside it and have no acoustic signature either. change from engines...to electric motors, same as quiet AIP submarines. except, this can move through the air at speeds several times faster than a surface ship.......and then, across land as well. Is a stealthy airship a real possiblity? certainly. (remember the radome) and check back......in 1999, Lockheed Martin announced they had designed an airship ¨the size of two soccer fields¨ and shaped similar to the B-2 bomber..... me....I think that P-791 is not really a POS...it´s just an expensive bit of ..............disinformation. cute!