Sudden appearance & equally abrupt disappearance of illuminated & extremely fast UFO flying in the night sky above I-75 South.WHEN: May 31, 2010, at approximately 12:50 a.m.WHERE: Driving South on I-75, about 2 miles before reaching the Williamsburg, KY, exit SIGHTING: An unidentified object flew across the night sky just above the road in front of us; it appeared and illuminated suddenly and seemingly from nowhere, moved extremely fast in a straight line (although it seemed to move slightly forward across the sky), and just as suddenly, completely disappeared seconds later SUMMARY: While driving home to western NC from Berea, KY, a friend and I observed what neither of us can logically explain as anything other than a UFO. [OBSERVER 1/INCIDENT REPORTER BACKGROUND INFO.] Being both an avid astronomy enthusiast and the daughter of a retired USAF fighter pilot, I believe that I am a very good judge of determining the “identity” or cause of an illuminated and/or moving object in the sky. Not only do I have a strong knowledge of what things in the night sky such as meteors/”shooting stars,” satellite/ iridium flares, planes, helicopters, etc., look like, but I also have a healthy dose of analytical skepticism from my father which I always apply when something out of the ordinary presents itself.When the topic of a UFO is brought up, I always think of the story of the “Tucson Lights” ((NUFORC Note: ((sic)) Phoenix Lights)) that is shown on UFO shows on TV often and hoe my father finds it slightly comical how much that incident is still hyped despite the lights so clearly (at least to him) being from A-10 flares (he was an A-10 pilot for 20 years, with over 4,000 hours in the cockpit). However, my father has always been deeply fascinated by UFO stories/sightings, and he is a firm believer that much more happened at Roswell in 1947 than what the government ever told the public. My father has instilled in me a profound love and curiosity for all things flight and/or outer space related, as well as a strong sense of the importance of thoroughly reviewing/examining something before drawing any conclusions.ADDITIONAL NOTES ON SIGHTING] The object did not enter from one end of our line of sight and exit at the other, but rather, it suddenly appeared in the middle region of the night sky visible in front of us, and seconds later, disappeared directly in plain sight. It did not have the movement, luminosity, or any of the distinguishing characteristics of a meteor. Although it appeared to be an illuminated aircraft of sorts (not just a streak of light), it moved far too fast to be a plane as well as in a somewhat hard to explain irregular path unlike that of any airplane. Additionally, its light was not constant like that of a plane in the night sky. It simply appeared in the middle of plain sight, moved across the sky in a way and at a speed that I have never before witnessed demonstrated by anything else, and then abruptly vanished while still in a clear area in the middle region of the night sky visible to us.Having observed a comet, several meteor showers, a satellite flare, and of course, more planes and helicopters than I could ever hope to count, move through the night sky, what I saw in the sky this past night was almost bewildering, due to it being absolutely unidentifiable in any right.