The Sixth Army, in the midst of chaos, began to build defensive lines, hampered by the lack of fuel, ammunition and rations, and further burdened by the advancing Russian winter. It was also tasked with plugging gaps in the line caused by the disintegrating Romanian forces. On 23 November, some German units destroyed or burned everything not necessary for a breakout operation and began to pull back towards the northern end of Stalingrad. However, after the Germans had abandoned their winter bunkers, the Soviet 62nd Army was able to destroy the German 94th Infantry Division on the open ground; survivors of the German division were attached to the 16th and 24th Panzer Divisions. Although German military commanders were of the opinion that "Heer" forces caught in the encirclement should break out, between 23 and 24 November Hitler decided instead to hold the position and attempt to resupply the Sixth Army by air. The personnel trapped in Stalingrad would require at least of supplies per day, a task which the depleted "Luftwaffe" was in no condition to carry out. Furthermore, the revived Red Air Force was a threat to German aircraft attempting to fly over the encirclement. Although by December the "Luftwaffe" had assembled a fleet of around 500 aircraft, this was still insufficient to supply the Sixth Army and elements of the Fourth Panzer Army with the required supplies. During the first half of December the Sixth Army received less than 20% of their daily requirements.