I saw swamp gas reflecting headlights and tail lights into the sky. From a distance of a mile, it appeared to be “mysterious” lights in the sky, darting hither and yon.
It can explain some sightings, but simply doesn’t explain many others recorded by credible observers and analyzed by scientifically knowledgeable people.
Hynek suggested it once as a possible explanation for *some* perceived ‘ufos’; but the press ran with that and it became a ridiculous ‘meme’ to people who had seriously studied the data from many sightings.
(Another misconception is that Kenneth Arnold saw ‘saucer-shaped’ objects near Mt. Rainier. He never said that. He saw somewhat ‘wedge’-shaped objects, apparently curved on one edge, that MOVED as a saucer might, if skipped over water. But, the notion of ‘flying saucers’ became embedded in the ‘lore’.)