The director of "Luftflotte" 4, Wolfram von Richthofen, tried to get this decision overturned. The forces under the 6th Army were almost twice as large as a regular German army unit, plus there was also a corps of the 4th Panzer Army trapped in the pocket. Due to a limited number of available aircraft and having only one available airfield, at Pitomnik, the "Luftwaffe" could only deliver 105 tonnes of supplies per day, only a fraction of the minimum 750 tonnes that both Paulus and Zeitzler estimated the 6th Army needed. To supplement the limited number of Junkers Ju 52 transports, the Germans pressed other aircraft into the role, such as the Heinkel He 177 bomber (some bombers performed adequately – the Heinkel He 111 proved to be quite capable and was much faster than the Ju 52). General Richthofen informed Manstein on 27 November of the small transport capacity of the Luftwaffe and the impossibility of supplying 300 tons a day by air. Manstein now saw the enormous technical difficulties of a supply by air of these dimensions. The next day he made a six-page situation report to the general staff. Based on the information of the expert Richthofen, he declared that contrary to the example of the pocket of Demyansk the permanent supply by air would be impossible. If only a narrow link could be established to Sixth Army, he proposed that this should be used to pull it out from the encirclement, and said that the Luftwaffe should instead of supplies deliver only enough ammunition and fuel for a breakout attempt. He acknowledged the heavy moral sacrifice that giving up Stalingrad would mean, but this would be made easier to bear by conserving the combat power of the Sixth Army and regaining the initiative. He ignored the limited mobility of the army and the difficulties of disengaging the Soviets. Hitler reiterated that the Sixth Army would stay at Stalingrad and that the air bridge would supply it until the encirclement was broken by a new German offensive.