From being a secret Nazi weapon to being merely static electricity, here is another article (published in 1945) explaining away the foo fighters spotted by pilots during WWII.
Foo Fighters Only Static, Transport Pilot Believes
“Foo fighters” are static, says Lt. G.C. Claybrook, Army transport pilot.
The mysterious balls of fire have been sighted by Yank pilots in Germany. Some have suggested they are a new Nazi weapon sent up to race beside invading planes for psychological effect.
“The ‘foo fighter’ is a concentrated mass of static electricity caused by the tremendous speed of the plane in passing through a rain cloud,” the pilot asserted. “It is familiarly known to most pilots as ‘St. Elmo’s fire.'”
He said he had encountered the balls of fire in the cockpit and has seen them advance around the sides and floor of his plane.
Lt. Claybrook is here for reassignment after flying a transport on 162 missions over the hump in India.
Source: Evening star. [volume] (Washington, D.C.), 10 Jan. 1945.
