I went outside to watch the ISS go overhead and take some photographs. About 2 minutes before it showed up, I spotted the UFO. It was equilateral triangular shaped, with small white lights at each of the corners and a larger red light in the center. As it passed, I heard a jet engine noise from the craft. I am quite certain that what I spotted was an aircraft of some sort. However, I did not spot anything that made it look like a conventional craft. There were no navigation lights, no flashing strobe, and the one large red light seemed to be under the craft. I did not see any windows, expect maybe when I first spotted it, but as the craft went overhead, whatever the windows might have been disappeared from view. There are no air force bases nearby, and the craft was traveling at the same apparent speed as a high altitude passenger aircraft. As the ISS came into view, the UFO went behind some cumulus clouds and vanished from view. I tried to take a photograph of it, but it was too dark.