That is correct T.A.!
Also once Milch took over the operation (14 January Hitler ordered Field Marshal Erhard Milch to take over the air resupply of the Stalingrad pocket)it was his obsession to use gliders to take supplies to Stalingrad and even once he had given up the idea every third train (!) was bringing gliders to the front. This also from " Stopped at Stalingrad ".