Kenneth Arnold (1915-1984) was an American businessman, aviator, and author whose 1947 UFO sighting near Mount Rainier, Washington, ignited the modern UFO era. On June 24, 1947, while piloting a CallAir A-2 and searching for a missing Marine Corps C-46 transport plane, Arnold made his historic observation. He spotted nine shiny, crescent-shaped objects flying in echelon formation near Mount Rainier, traveling at speeds exceeding 1,200 mph—three times faster than any known aircraft. Arnold described their motion as "like a saucer if you skip it across water," a phrase that, via media reports, coined the term "flying saucer." As a licensed pilot with extensive flying experience, Arnold provided a credible eyewitness account that sparked widespread attention and official scrutiny.
Arnold's sighting prompted over 800 sightings nationwide that summer and triggered U.S. government and military investigations into unidentified aerial phenomena. He testified before Air Force Project Sign investigators, and his sighting was classified as a "Daylight Disc" in Hynek's classification system.
Arnold became a pivotal figure in UFO research through his writings and continued investigations. He co-authored "The Coming of the Saucers" (1950) with Ray Palmer, detailing his encounter and theories on extraterrestrial origins, and pursued further anomalies, including the 1949 Maury Island incident. His sighting remains a cornerstone of UFO history despite ongoing skepticism.