Foo Fighters of World War II Blog :
Mysterious Aerial Phenomenon seen in the skies over both the European and Pacific theaters of Operations. Though "Foo Fighter" initially describes a type of UFO reported and named by the U.S 415 Night Fighter Squadron, the term was also commonly used to mean any UFO sighting for that period. Formally reported from November 1944 onward, witness often assumed that the Foo Fighters were secret weapons employed by the enemy. The Robertson Panel explored possible explanations, for instance that they were electrostatic phenomena, or simply reflections of light from Ice Crystals.
The first sightings occurred in November 1944, when pilots flying over Germany by night reported seeing fast-moving round objects following their Aircraft. The objects were variously described as fiery, and glowing red, white or orange. Some Pilots described them as Christmas Lights and reported that they seemed to toy with the aircraft, making wild turns before vanishing. Trained battle hardened Fighter Pilots witnessed these unusual Aerial Phenomena in the theatres of Operations.