 By noon of 7 August , the early morning fog had dispersed , and large numbers of Allied aircraft appeared over the battlefield . With the advance knowledge of the attack provided by Ultra , the U.S. 9th Air Force had been reinforced by the RAF Second Tactical Air Force . Despite assurances by the Luftwaffe that German forces would have adequate air support , the Allied aircraft quickly achieved complete control of the airspace over Mortain . The Luftwaffe reported that its fighters were engaged by Allied aircraft from the moment they took off , and were unable even to reach the battlefield . In the open ground east of Mortain , the German Panzers became exposed targets , especially for rocket @-@ firing Hawker Typhoon fighter bombers of the RAF . 
