Imagine a really cold morning, one cold enough to see your own exhaled breath, or a car exhaust... A "contrail" (short for CONdensation TRAIL) from a jet aircraft is nothing different. You'll see them in the summer time as well, as while it's warm here on the surface, it's still cold way up there where the engines are operating...
That said, there is a certain percentage of the general population that is convinced that these contrails are actually chemtrails, and that some ee-vil substances are being intentionally "sprayed" on us for some supposedly nefarious purpose(s) by the government. As should be evident by the use of low-flying cropdusters spraying crops, if you want to spray something -on- the ground, you have to be -close- to the ground, and -not- up above 30,000 feet.
Anyone who works in airline aviation -knows- that they're really contrails, but of course, the chemtrail crowd spins that around as "proof" that we airline employees are thus all in on the "cover-up". Yeah, right...
[Edited 2004-08-22 22:58:41]
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.