TOWER: Southwest 1256, I don’t know if it’s normal I just haven’t seen it that low; it appears like a chemtrail-type situation off your left wing.
PILOT: Say again Southwest 1256?
TOWER: Southwest 1256, it looks like a chemtrail off your left wing, I just have not seen it that low before, but it does look similar to a… (transmission cuts out)
PILOT: Ah, OK, thanks.
TOWER: Alright, a contrail off your left wing
PILOT: OK,thank you.http://www.tankerenemy.com/2016/10/controllore-di-volo-segnala.html?showComment=1475682173115#c1096088872923448651