Hello majicbar,
Let's not forget at first that the video is split onto 4 sequences (2'23" for the first one, 19" for the second, 1'13" for the third and 53" for the last). So it's impossible to say that all flares can be visible over four minutes.
Then, about the geometrical aspect that leads you to think that they string out into a line, let's see how flares can be ejected off the jet:
... almost a perfect line. Same goes as well for parachutes flare, they can be ejected in a line if the jet fly this way.
Add to this:
- The distance from the camera that reduce the apparent flare distance between each other.
- The flares are all made equally, with the same material, same parachute (if they are equipped with parachutes), etc... so they act in this small sky space almost as a whole to the local weather conditions, slowly going down and finally slowly separate as time goes by before fading away.