The Foo Fighters of World War II
The account
Balls of light chased Allied aircraft across the skies of Europe, matching every maneuver.
What investigators found
The most widely accepted explanations are St. Elmo's fire, reflections, electrical phenomena and the extreme fatigue of pilots in combat.
The story
In late 1944, crews of American night fighters flying over Germany began reporting bright lights, red, orange or white, that seemed to follow their planes and slip away from any attempt to close in. The airmen nicknamed the lights foo fighters, a phrase borrowed from a comic strip of the time. Similar reports came from other fronts of the war, including from pilots on the other side of the conflict.
At the time, the military feared it was a secret German weapon, but nothing of the kind was found after the war. Today, researchers point to natural and human explanations: St. Elmo's fire, an electrical discharge that glows on metal structures; light reflecting off clouds and off the aircraft itself; flames from other planes; and the exhaustion of crews flying long night missions. The case became a landmark of modern ufology.