Airbone white lines over NY metro area

For the past 45 minutes, I have been seeing quite a few planes flying in the direction of NYC releasing lines of condensed airborne material, all traveling in parallel, spread out for some miles. Quite a few, meaning at least 10> within my limit range of sight. It seems that the material is spreading out across the area of the sky, and does not appear to be dissipating - only evening out.

It is a clear blue sky today, and the planes are actually generating clouds from their leftover exhaust/whatever... 45 minutes later.

I don't think that jet fuel does that normally.