I ask because this morning, for the first time I can remember, I looked up and saw a contrail which looped back on itself. A classic ‘teardrop’ shape. This was some few ten of miles (probably) southeast of Dulles airport, and whatever plane left it behind would have been heading northeast after the turn. Ten minutes later, there were two more U-turn contrails up in the same patch of sky, with the same orientation (and the first had a pretty little sundog in it). I saw the first at about 8:50 AM eastern time, and couldn’t help but think about the events of almost exactly a week ago.
Which way is the wind heading this morning? If it’s coming from the southeast, there’s your answer. Planes take off into the wind. Where they go after that is accomplished through turns. 
You probably just noticed it because you’re more aware of turning planes now.
IANAP, but that’s my guess, anyway.
I always thought planes took off in the direction of the runway.
Obviously they do… but which direction down the runway they go depends on the direction of the wind… they go into it as much as possible
Wind may be the answer, but not as it affects takeoff. There may have been a localized jet stream that deflected the contrail or the plane may have climbed through layers that had different wind directions. That is, the plane may have been on a straight course and the contrail was deflected by wind.
Since you’re fairly close to the airport, it may also be a result of aircraft maneuvering in and out of the landing pattern. They may have severely restricted access to the airspace over Washington for the moment, which would cause aircraft to jump through hoops to enter and leave.
Or maybe they’re re-enacting the scene of the crime for study purposes.
Perhaps they had to abort a landing and were going-about for a second attempt
Just a note about aborted landings, etc. A persistant contrail would not occur so clost to the ground. It needs to be up in the cold, cold air.
Aircraft in cruise may turn around for any number of reasons. A commercial jet may have some sort of emergency or in indication that there is an emergency and turn toward the nearest airport. A military jet may have reached the end of its patrol area or is engaged in a maneuver.
Yes I havew been in a plane that made a U-turn at high (or at least higher) altitude. About 10 minutes before landing fog closed the airport and we turned around.
Flymaster, the turn-around after take-off is out. I’ve seen too many of those right at Dulles. These were contrails I was seeing, and they lasted at least half an hour. I’m guessing their altitude was at least 20,000 feet. Secondly, if you’re going to turn around as part of a flight plan (say, a long-distance turn-around after takeoff), would you take the time and effort to turn around so precisely (‘teardrop shape’, remember - they basically followed their own contrail back towards wherever they came from), or would you just make a big U?
Micco, I was close enough to it at one point in time that I had to lean over my steering wheel to be able to see the whole thing through the windshield. In other words, I was looking up at a rather steep angle. I can’t imagine a wind or set of winds which could bend a straight contrail back around on itself without shredding it (if you hypothesize winds of different directions at different altitudes, there will be gaps in the contrail after a short time).
Attrayant, I loved the ‘runway’ answer. I guess it’s possible that someone was doing some sort of reenactment, but I don’t see what the purpose would be unless they were doing it for “how’s it look from the ground?” kind of questions, in which case I’d think they’d do them where they actually occured (NY, KY, OH).
And ticker, if you’re going to try for another landing, I’m pretty sure you wouldn’t bother going back up to umpty-ump thousand feet to do so. You’d also probably circle around completely, since not only do you want to take off into the wind as much as possible, you want to land into the wind as well.
Johnny LA, I missed your reply on preview. Huh. Anyway, I’m going to guess, without further info, that the military aircraft on partol idea is probably closest to the truth. Unfortunately, I didn’t actually see any aircraft in the process of making these contrails (too busy driving), but three of them doing the same thing in the same direction in the same airspace in such a short period of time seems like just too much for commercial craft in emergency situations.
But then, if I knew what was going on, I wouldn’t be asking.
Here’s my WAGs:
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It could be something was going on in the airspace the jets were about to enter and air traffic control (ATC) asked them to do a 180.
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A “teardrop” shaped flight path is sometimes used when “holding” over a specific spot while waiting for a clearance from ATC. Since airplanes don’t hover very well (unlike Johnny LA’s favoriate aircraft) they have to circle or otherwise fly a closed loop. These holds can be at a variety of altitudes, and if particularly busy ATC can stack planes at various levels. If something was happening that would slow down air traffic several jets might, conceiveably, be asked to hold at high altitude and therefore fly a “teardrop”.
For instance, if there was an emergency on the ground that temporarially closed the runway(s) they might hold jets at a high altitude to keep them clear of smoke, out of the way of other aircraft, and so forth until ATC can get everyone sorted out to alternate destinations or the emergency ends.