The event was among the most publicized early UFO incidents. Later investigations by the US Air Force’s Project Blue Book indicated that Mantell may have died chasing a Skyhook balloon, which in 1948 was a top-secret project he was not aware of.
Mantell chased the object up a steep climb and disregarded suggestions to level its altitude. At high altitude, he passed out from lack of oxygen; His plane went into a downward spiral and crashed.
In 1956 Air Force Captain Edward J. Ruppelt (the first head of Project Blue Book) wrote that the Mantell crash was one of three “classic” UFO cases in 1948 that would help set the UFO phenomenon in the public mind and help convince some Air Force intelligence experts that UFOs were a “REAL” physical phenomenon.
Somewhere in the Air Force or Navy archives are records that will show whether or not a balloon was launched from Clinton County Air Force Base, Ohio, on January 7, 1948. Captain Edward J. Ruppelt was never able to find these records. .
People who were working on the first skyhook projects “remember” operating at Clinton County Air Force Base in 1947, but refuse to limit themselves to a January 7 flight.