Silver sphere surrounded by a gas cloud hovering

Bright silver sphere surrounded by what I can only describe as a gaseous cloud ( like what you would see coming off a hot road) but very specific/rigid in shape. I never saw the object move, but looking away at times since the experience lasted so long, I lost track of it, but each time was in a different location and far from the previous place. Size was about the same as the body of a normal helicopter. saw numerous planes and choppers immediately after in the same area so I was able to reference size