Chem/contrail?

[zorgon]

No spraying here at all.  The dense cloud across the plane is pure condensation from the pressure change. The two contrails are actually created by wing tip vortex  If you want to deny wing tip vortex  is real, I suggest you never try flying a Cesna into one It will tear your wings off

[ArMaP]

How about this for some kind of evidence?

http://www.chemtrailcentral.com/report.shtml

That's a good report, but it's only evidence that persistent contrails exist, and that the aeroplanes that created the persistent contrails included in the report did not appear on a specific flight tracking application.

[micjer]

Some good productive evidence/discussion on this topic.  Looks like they have been around longer than first thought.

At least in this case we know that NASA will be doing it.

NASA Releasing Artificial Clouds Over Maryland Coast


http://www.naturalblaze.com/2017/06/nasa-releasing-artificial-clouds-maryland-coast.html

JUNE 1, 2017