No. 93: May-Jun 1994
T. Surendonk has written to New Scientist how he and a friend would stop on Sepulveda Boulevard, at the edge of the Los Angeles airport, to watch the big jets come in directly overhead for a landing.
"While the huge planes were impressive enough, our attention was captured by an event that sometimes occurred between twenty and thirty seconds after a plane had flown over: a thin tube of misty air would zap past us at apparently high speed accompanied by a rather loud flapping sound.
"Sometimes the "mist" would follow a straight path, but often it would follow a really contorted path that made the "mist" look like a snake engaged in a rather violent path -- rather captivating to watch. "We suspected that the effect was some sort of remnant of the vapour trails that sometimes came off the tips of the wings and tried to confirm this by direct observation, but we could never keep track of such a trail for more than 5 seconds. Also, we were never totally convinced that the two effects were correlated. Anyway, wouldn't such a trail dissipate within a few seconds?"
(Surendonk, Timothy; "Just Plane Weird," New Scientist, p. 58, March 5, 1994.)
Comment. If these "mists" are merely trailing vortices, the long time delay between passage of the plane and the tube of mist is puzzling.