I went to an airshow at an airbase one time. Planes flying, planes on display outside, and in hangars. Part of one hangar was empty, and roped off. Joking with one of the pilots, we decided to put up a sign: XF-115B Second Generation Stealth Fighter (Cloaked Mode). When I went back later he said some people had said they were sure they could see it if they squinted, or if the light was just right, etc.