I believe panning is a VERY good thing to do, especially with the new digital photographers who never shot film.
Here is why:
1. You learn to control lower shutter speeds. This is important because it gets you in the habit of shooting props or helicopters at slow speeds while maintaining focus on the subject. The biggest mistake new digital photographers do (and it is a very critical error in aviation photography) is frozen props. When we shot film, slide film was very slow to process thus high speed shutters would not expose the corners correctly leaving them dark (tunnel effect) otherwise called "vignetting" in photography. We then had to shoot almost all action at 1/250 or lower. This got us in the groove of shooting slow shutters with very steady hands. Back then we did not have vibration control or autofocus (which you do not need if you are a good photographer today). Try it. I would suggest you shoot all action at lower shutter speeds to get used to it. You WILL lose a few shots but the practice will make you a better aviation photographer in the future.
2. The panning gives a nice speed effect on action shots.