And, a pretty steep climb also. That's fighter territory, not airliner. Or, missile territory...
And how would he have any idea how fast it was moving? You have a video shot from a moving helicopter, of an object at extreme distance, filmed zoomed in with no other features visible (except that at some point, a plane flies across the screen in about 6 seconds, which should be a clue about how zoomed in we are).
So far as you can tell from the video, the thing is hardly moving at all.
Look at the zoomed-in part where you think it is “moving”, and watch the contrail features. You will see that the features stay a constant distance from the “moving object”, which means if the object is moving, it is dragging it’s contrail with it.