Just like my post about not having any Artillery in my Space Wolves or Mentor Legion armies. I also didn't have any anti aircraft weapons so as luck would have it i had done a model swap about a year ago and remembered that there was some hunter turrets included.
To add a bit more detail on my Wolves ones i cut away the left side bolter turret and replaced it with a radar dish. This was made by cutting a thin piece of plastic tube and drilling a hole and gluing it in. The dish is cut from an old rough riders base, then cut in half and angled inwards.