 Complete the following phrase:  Attritional air battle alarmingly depleted the Luftwaffes strength. 911 aircraft were lost in July, while inflicting much heavier losses on the Soviet Air Forces, whose strength appeared to be undiminished. The Soviet 11th Guards Army initiated an offensive aimed at cutting off the 2. Panzerarmee and German 9th Army. The Luftwaffe was called upon to rescue the situation in a huge aerial counter-offensive lasting from 16 July31 July against a 