I had a fascination for jet trails when I was a kid, late fifties early sixties, because we saw very few jets going over. Donuel, you say: "con trails dissipate in seconds or minutes.", but that isn't true, they can linger for hours, depending on atmospheric conditions - I remember the effect from childhood, of the slowly spreading stripe on a clear blue sky, long after the plane was gone. Even if what you say is really occurring, I seriously doubt single Canadian jets over Cape Breton were performing these experiments in that era.