During a late-night visual approach, at four or five thousand feet, I had a glowing object pass from left to right across the nose at great speed, traversing from my left horizon to the right extreme in 1-2 seconds on a windy dry night when visibilities were easily greater than 100 miles. It had a very flat, low-angle, descending trajectory - was white-orange at first, then seemed to skip upward a few degrees and become quite greenish as it vanished to the west , presumably behind a range of hills some 60 or 80 miles distant. Boggles the mind, but the geometry of its traverse suggests a velocity on the order of 10,000 kts!
After we landed, the 24-hour weather observer radio'd to ask me into his bright lit office in the terminal building. He had received calls, despite the midnight hour, from local people who were excited about 'something' in the sky. "What had I seen?", he asked. As we conversed, he put the same query on radio to another aircraft that was making a quick turnaround.
Upshot of the process was that the other aircraft had been approaching the airfield on an opposite heading, but at similar altitude. He had seen what I saw, in mirror image. The only conclusion one could draw was that this phenom had passed right between our two aircraft, no more than ten miles apart. The brilliant hypersonic object I had imagined to be fifty miles ahead was likely distant only four or five.