I noticed that too. Snypirs vehiclecam works perfectly
You have to execute the script in your camscript itself,not in a trigger, waypoint or whatever...
The bouncing is not caused by the script, but by the heli or plane.
I suggest you wait until the plane reaches his cruising speed before you attach the camera.
Try the vehiclecam with a car or truck and you will see no bouncing. I had the same problem with my
logiccam.
Attaching camera's to heli's or planes is a bit tricky...