Posted May 29, 2011
I have seen them at about that length. I think it depends on the temp at that altitude. The colder it is up there, the longer the contrail. As for seeing them at night, I guess it is possible at the right time. The sun would have to be far enough below the horizon for it to be nearly dark but still in a position when the rays would still reflect off of the contrails, which would also depend on the altitude at which the plane is flying. I have seen this with clouds. Kind of weird.