Have any of you guys seen a big, white with a little blue, 4 engine prop job (reminds me of a C130), flying around the Denver area lately? We first saw it flying low, Thursday the 17th, over downtown Denver circling and gradually getting higher. Then we saw it Monday the 21st, up by Dacono circling low. Then we saw it the next day, Tuesday, flying around the Chatfield area circling low. It was weird that we saw it so many times in different locations. We're pretty certain it was the same plane each time. It looked like it had a bit of a tail boom like a re-fueler.