I tested the Mosquito and Typhoon. It probably happens on all aircraft.
Select the Mosquito or Typhoon in the hangar, give it rockets and click on a start loacation to move into the aircraft.
Adjust your head position so that the rockets and the rocket rails are visible from the cockpit.
Use the zoom in function to zoom all the way in and out.
RESULT:
At maximum zoom in the rockets and rocket rails disappear.
