text:  As part of a combined @-@ force operation , the German Air Force ( Luftwaffe ) would contribute Ju <unk> , Stukas , Messerschmitts , three light AA battalions , and three heavy AA battalions . Nazi Germany 's Kriegsmarine would cooperate by using U @-@ boats to interfere with British naval movement and emplacing coastal batteries to further discourage the Royal Navy . 
  