Note: Thanks to FreeViewDocumentaries for this find
I've heard enough denial of this observable activity. It's obvious here in Charlottesville, very noticable from 810 going from Whitehall to Crozet, VA. Many days are changed from blue skies to white haze in a matter of hours. The planes usually fly across prevailing winds allowing the initially dense thin line behind the plane to blow into a sheet as it is carried by the wind. Multiple lines, parallel and sometimes at angles are added, many times two jets flying a formation.
Oh - the day Obama was in town months ago was the clearest day I've seen in a long long time. He was speaking downtown, and there were no persistent contrails that day. The next day they started anew with a vengeance - until the skies were an ugly aluminum overcast.