Although gremlins are a recent addition to the folklore of the wee folk, it would seem that their antecedents are the goblins of old. The term "gremlin" was derived from the Old English word greme, which means to vex and annoy. And that is certainly what the gremlins did to the pilots and their aircraft in World War II (1939–45) when the pesky entities were routinely blamed for engine troubles, electronic failures, and any other thing that might go wrong with an airplane.
Although the tales of gremlins received their greatest notoriety annoying the pilots of Great Britain's Royal Air Force (RAF) in the period 1940–45, Dave Stern, an aerospace, aviation, and history writer, says that the legend began in 1923 when a British navy pilot crashed into the sea. Once he was rescued, he blamed the accident on some little people who had jumped out of a beer bottle and had tormented him all night. It was these wee trouble-makers who had followed him into the airplane, entered into the engine, messed with the flight controls, and caused him to crash. Not long after this reported gremlin attack, some pilots and mechanics stationed at an overseas RAF aerodrome complained of being bothered by the annoying entities, and by 1925, British pilots were cussing the little monsters and blaming gremlins for almost anything that might possibly go wrong with their aircraft.
According to airmen who swore that they had survived close encounters with the mischief makers, the gremlins dressed in red or green double-breasted frock coats, old-fashioned tricorn hats with a feather (or sometimes stocking caps with tassels at high altitudes), tights, and pointed footwear. Some of the gremlins loved to suck the high octane gas out of the tanks; others messed with the landing gears; and still others specialized in jamming the radio frequencies. Just as the pilots and mechanics were learning to respect the gremlin crowd, it wasn't long before they also began to be annoyed by the gremlins' girl-friends, the finellas, nicknamed the widgets.
When the U.S. Army Air Force pilots were stationed in Great Britain after the United States entered World War II in December 1941, they found the gremlins waiting for them. The men may have scoffed at their allies at first, but they were soon suffering unexplained attacks on their instrument panels, their bombing sights, and the de-icer mechanisms. The Yanks found that they had also fallen victims to the annoying antics of the gremlins.
Although the most intense activity of the gremlin throng occurred during World War II, one stills hears on occasion a pilot cussing a mechanical failure in his aircraft as having been caused by a gremlin attack.