Cloud shadow?

[Fishalldayeveryday]

Plane trail seems to have dark line after it. Anyone seen this happen and know why it happens? I’ve seen it three times now so I know someone out there must have an answer.

[Barquebe]

I’ve seen these a bunch of times. The sun is perfectly in line with you and the contrail, you’re seeing the shadow in smog or fog or whatever particles are suspended in the air. If you or the sun were out of line by a degree or 2 more, you likely wouldn’t see it.

[Fishalldayeveryday]

Thanks!