@HealingHobbit As someone who worked in the aviation industry, those are perfectly normal contrails. Atmospheric conditions cause them to behave differently.
@HealingHobbit I guarantee they aren't at the same level. If you know which direction they were going and when, you can look the flights up on flightaware.com Even 500' difference in altitude can have huge differences in jetstream/wind impacting dissipation.
@ehurtley Oh, cool, thanks!!
@ehurtley These two (couldn't get the lower one quick enough) were about the same level (guessing) yet the one's trail is completely gone and the other is spreading. This only happens once in a while with the trails like this; usually they all disappear quickly. And the weather conditions vary.