In article . com,
wrote:

well if anyone knows you guys should! what is this phenomena all about?
we all can see normal contrails but the other sort - the ones that just
hang in the air and spread wider and wider forming fake cirrus clouds,
are we being poisened, are they reflecting back sunlight? and who is
involved with it.
this is a genuine request for information and I would be very grateful
for your comments.

No mystery, no conspiracy.

It is all due to atmospheric conditions. Supersaturated air at altitude
allows contrails to promote further cloud formation.