On the buoyant cigar shaped UFO the forward drive band corresponds to the transparent bands on my UFO lab model. This is where waves of plus ions followed by minus ions in rapid succession are accelerated. In the big UFO by high frequency AC in the same direction for which reason high power at high AC voltage the band appears black or grey because it is made if high temperature fused thorium oxide or fused tungsten oxide by three dimensional laser powder melt in a vacuum to exclude bubbles. Neither are transparent. Fused tungsten oxide is black. The aliens go first class. No cheap stuff.