It's believed that governments worldwide are working on top secret classified aircraft, as many strange objects have been spotted in the skies recently. However, not all of these are man-made, or so we'd like to think. A notable incident is the disappearance of 20-year-old Frederick Valentich while on a 125-mile (235 km) training flight in a Cessna 182L light aircraft over Bass Strait in Australia on October 21, 1978. Described as a "flying saucer enthusiast", Valentich radioed Melbourne air traffic control that he was being accompanied by an aircraft about 1,000 feet (300 m) above him, that his engine had begun running roughly, and finally reported, "It's not an aircraft." UFOlogists have speculated that extraterrestrials either destroyed Valentich's plane or abducted him, asserting that some individuals reported seeing "an erratically moving green light in the sky" and that he was "in a steep dive at the time." Ufologists believe these accounts are significant because of the "green light" mentioned in Valentich's radio transmission. Continue reading for more.