Thats not exactly the true...Stalingrad was very important because of the 4 supply routes that met there. Oil, Coal and Ore were needed in Germany and all this runs through Stalingrad. The other point was the moral effect to capture a City with the Name of the russian Leader, so Hitler ordered to take it and with all the Victorys in the past, it seemed to be just another Town which could be taken easily...
After the surrounding of the 6th Army, Göring said, that he can easily supply the 6th Army from Air. That was the biggest mistake and one of the biggest lies in the war, because the german Airforce wasnt able anymore to transport around 500 tons a Day of supplys because of lack of supplys, Planes, Crews and missing fighter cover...and anybody knew this at this time, even Hitler but he wanted this Town at all costs and still believed that a German Soldier is worth 10 enemies... (sorry, my english is not as good as i wish ).
Ok, back from this little historical lesson, i have to say, that the idea of Airsupply is really great....but to use a Fighter Group for it isnt very historical and i dont like this idea. Its a small difference between a german FW190 fighter and the common JU52 transport plane
Maybe there should be some extra Unite type "Transport" for this...the Allies had a DC3 as far as i know while the Axis had the JU52...i think it isnt to hard to add