Close Triangular Craft with red lights that hovered

I first saw what appeared to be a plane flying, and it was pretty high up and going at a rate of speed you would expect a plane to be traveling, then the craft began to descend and as it got closer, you could clearly see it was triangular in shape and the rate of speed had slowed so much that it appeared to be hovering and the. It rotated slightly and began traveling off in the opposite direction than it appeared to be going when I first noticed jt. It was definitely something surreal to see and It was something Id never seen before, ever!