Hilarious!- thanks for the chuckle.

Annon- Have you seen this page and video? Can you see how there might be some Xs and grids if contrails persisted?:

http://contrailscience.com/britain-from-above-air-traffic/

Again you’re shooting your self in the foot. Your excuse that it is down to different engines or newer engines again hold no water by the site you directed me to. In the site there are claims of contrails back as far as before ww2, this indicates to me that even prop aircraft leave contrails, now if this type can produce such phenomena then surely engines in the seventies and eighties would produce contrails and we should have had similar skies to what we are now experiencing. This is the part that is bugging me. Why the massive increase.

The different types of engines leaving or not leaving contrails is just basic science. You can google “contrail factor” if you want to get the details. It’s only one small part of the reason why there are more contrails today. The main reason is the huge increase in air traffic since the 1970. They had similar skies then, but with 1/4 the traffic it was less notable. Remember most people don’t even notice it now.

Why are they always following a pattern, they start by forming the St Andrews cross then continue on to the hash symbol , it is repetitive only when we get the influx of aircraft that normally do not use the airspace above us.

Or perhaps when you can SEE those planes. If they don’t leave trails, then how can you see them. The same planes fly over every day. If they leave trails, and hence if you can see them, depends on the weather at the altitude they are flying.

The cross then the hash pattern is quite simple. You are at the rough intersection of some international routes. The wind at that altitude is usually above 80 mph. Two planes fly along, and they leave a cross. Two more fly along 15 minutes later, the trails have been moved 20 miles by the wind, so you get a hash.

If you live anywhere that planes cross paths, you get the hash. Sometimes there’s a lot more traffic in one direction, so you get an H or –|-|-|–|—, or just a lot of parallel trails (that’s what I get here, occasionally crossed by planes going to Hawaii).

It is easy enough to claim it is water vapor but have you tested the air above Edinburgh when we allegedly get chem. Trails, no you haven’t but because contrails are real and proven you automatically assume that this is what they are. Until air tests are carried out to prove different by both parties then we will never know for certain what is really happening.

Contrails are water. These trails look exactly like contrails. So what is the evidence that says they should be tested? Would you test the Queen to see if she was a lizard, just because some people claim that she is. I think people would need a bit more evidence.

I have just finished repairing my camera so the next time it happens I will film it from start to finish, it has an excellent digital zoom that will allow a close steady view of the aircraft responsible so when you get a chance to see what I am seeing I will expect an honest reply using your expertise .

I look forward to it.

And I’m amazed that you have chosen to argue about aviation with a person whose lifelong profession is aviation when you yourself admit you are not a pilot. By the way- how’s Edinburgh doing today? What approaches are they shooting? What arrivals are they using?

And you say there are jets that travel through the trails that leave different trails? What are the EGTs of all the jets? How about even the general power settings? Anti-ice on or off? Nacelle heats on or off? You are obviously so knowledgeable about the specifics you must surely know that info as well.

Ok we have different makes and size of engine but they all emit exhaust so should leave similar trail even though emitting a different quantity of exhaust.

Not true. You need to read this, which was previously linked.

http://contrailscience.com/why-do-some-planes-leave-long-trails-but-others-dont/

However, those are NOT the planes that leave contrails. They are too low.

Planes that leave contrails above you are usually travelling to and from airport that are hundreds (or even thousands) of miles away from you. By the time they get to you they have made many course deviations for various reasons (weather and traffic being the most common), and are no longer on a pre-defined route.

When people say a plane is flying a pattern, they frequently are mistaking multiple jets flying in oposite directions for a single jet flying back and forth.

What year did you first notice this “type of sky”? Do you have any photos or video that illustrate this?

The atmosphere is not a uniform, static environment. Its moves like a fluid and thus has ares of varying conditions. Why are there clouds in spot but not another?

2 planes could simply be 1000 feet apart in altitude and be in different ambient conditions. All it takes is a few degrees diff in temp or a few % change in humidity to change the characteristic of the trail…

Even different engines have different trail parameters.

See here for Uncinus’ detailed analysis of this question that continues to perplex chemtrail devotees:

http://contrailscience.com/why-do-some-planes-leave-long-trails-but-others-dont/

What is a designated flight path? According to Capfitch- pilots can choose their own path from point A to point B….Is that correct?