western allied air forces held Hold air supremacy over the german reich and remaining Presence german-occupied territory .

although the partisans and chetniks had already irrevocably split in the german-occupied territory of serbia following operation Military_operation uzice , this had not yet happened Presence in eastern bosnia and in some areas they were still cooperating Collaboration .

the `` luftwaffe '' fighter force defended Defending the airspace of german-occupied territory against attack Attack , first by raf bomber command Causation and then against the united states army air forces ( usaaf ) .