Just after 2:00 A.M. several unidentified objects were reported over Los Angeles. The threat was perceived as the real deal; air raid sirens were sounded and a total blackout was ordered. At 3:16 A.M., the 37th Coast Artillery Brigade started launching 12.8-pound antiaircraft shells at the unidentified objects. Over the next 58 minutes more than 1,400 shells were fired as the objects moved south, from Santa Monica to Long Beach.
From the Sony PR sheet:
Descriptions of the UFOs varied widely. General George C. Marshall, in his initial memo to President Roosevelt regarding the event, wrote that the 'unidentified airplanes... [traveled at speeds ranging from] 'very slow' to as much as 200 mph and from elevations of 9000 to 18,000 feet.' The number of craft reported by observers ranged from 9 to 15 to 25.
At first, officials offered a very vague explanation. According to the Los Angeles Times (February 26, 1942), the secretary of the Navy, Frank Knox, dismissed the event as a "false alarm" due to "jittery nerves," but when this failed to satisfy the press and the public, the Army responded with a definitive answer that the craft and the battle were real, and the next day, Secretary of War Henry L. Stimson confirmed that. Santa Monica's US Representative, Leland Ford, was quoted in the Times on February 27 calling for a Congressional investigation into the incident, but this went nowhere. In the years since, various explanations have been offered – from Japanese planes to German craft launched from secret bases in Mexico to unidentified aircraft to weather balloons to sky lanterns to blimps.
However, it is also alleged that General Marshall reported that the Army had recovered an unidentified aircraft off the coast of California that indicated that the "mystery airplanes are in fact not earthly and according to secret intelligence sources they are in all probability of interplanetary origin.
What actually caused the battle - weather balloons, enemy recon planes, or UFOs - is still up for debate. We do know that the "UFO craze" didn't occur for another few years. Fighter pilots officially started using the term "foo fighter" for unidentified objects in November 1944, and Kenneth Arnold coined the term "flying saucer" in 1947 after seeing something he couldn't identify near Mt. Rainier. Not long after this UFOs become a national phenomena.
Be sure to read the full report about this event at The California State Military Museum's website as it adds quite a lot of additional information
Perhaps we'll never know what really happened, but it's fun to speculate. And really... what better way to do that then through the magic of cinema.
We want to know: Do you believe in UFOs, and have you ever seen one?