Thomas F. Mantell
Pilot who died in a crash while investigating a UFO that turned out to most likely be a Skyhook weather balloon.
In 1948, Captain Thomas F. Mantell with the Kentucky Air National Guard, responded to reports of a UFO. He and a group of other pilots in F-51 Mustang were near the sightings and were asked to investigate. Mantell got a visual of the object around 15,000 feet and reported that he saw "a metallic object of tremendous size." This ended being one of his last radio transmissions. Mantell continued to climb altitudes in hopes of getting a better look at the object. However, military regulations required that pilots never fly above 14,000 feet without an oxygen tank; Mantell reportedly did not have one with him.
All radio contact and visuals were lost with Mantell not long afterwards, and his crashed plane and body were later discovered in a Kentucky farm field. It was believed that Mantell had either lost consciousness or died from lack of oxygen prior to the crash. Even so, rumors began to swirl that Mantell had possibly been shot down by a flying saucer or a superior alien weapon.
Years later, with the release of declassified documents, it is believed that the unidentified object was actually a Skyhook weather balloon that the Navy had been using for experiments. At that time, neither the pilot nor personnel at the Godman Army base would have been aware of the still classified project.