The Germans had their giant glider that was later converted to a heavy transport by adding about six engines to it. I saw one picture of it unloading a light tank of some sort. By the by, I think gliders have a place in AH, but only if they carry something besides troops. Artie, a jeep, or perhaps a very light armored vehicle. Otherwise, I think simply taking a second C47 at low alt would serve you better than the C-47/glider pair.
An interesting historical note about the Allied glider-borne troops. Unlike the paratroopers, the glider troops did not get hazardous duty pay of any kind, even on D-day. Their casualties really were horrendous, too.
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Sabre, a.k.a. Rojo
(S-2, The Buccaneers)