
upload.wikimedia.org/wikipedia/commons/8/8b/B-17_Flying_Fortress.jpg
Also, I'm pretty sure I've seen clouds (made of water vapour) stay in the sky for longer than a minute. Maybe I was mistaken.
( ,
Thu 16 Apr 2009, 15:54,
archived)
Also, I'm pretty sure I've seen clouds (made of water vapour) stay in the sky for longer than a minute. Maybe I was mistaken.

And add this nail to the coffin:
"The first published reports of contrails appeared during and shortly after World War I when aircraft were finally able to reach the altitudes required for contrail formation. An early example of contrail formation was observed during the flights of the pilot Zeno Diemer in 1919, when he reached altitudes as high as 30,500 ft above Munich, Germany. "
( ,
Thu 16 Apr 2009, 16:00,
archived)
"The first published reports of contrails appeared during and shortly after World War I when aircraft were finally able to reach the altitudes required for contrail formation. An early example of contrail formation was observed during the flights of the pilot Zeno Diemer in 1919, when he reached altitudes as high as 30,500 ft above Munich, Germany. "

You don't know the difference between contrails and chemtrails? one disappears in a minute because it is frozen ice crystals, the other stays in sky for hours, and is a concoction of all sorts of chemicals and crap. But you never investigate it, you just sit and mastubate each other and giggle.
( ,
Thu 16 Apr 2009, 16:30,
archived)

it doesn't always disappear quickly.
A simple piece of investigation will tell you this
( ,
Thu 16 Apr 2009, 16:41,
archived)
A simple piece of investigation will tell you this

something to do with the introduction of a new kind of engine, like turbofans (randomly picked jargon word, may not in fact be turbofans).
Having said that, I remember seeing vapour trails a lot (particularly noticeable on summer days in a clear blue sky) when I was small, and I wasn't small in 1995.
( ,
Thu 16 Apr 2009, 16:01,
archived)
Having said that, I remember seeing vapour trails a lot (particularly noticeable on summer days in a clear blue sky) when I was small, and I wasn't small in 1995.