The Ju-322 Mammut (Mammoth) was an airborne glider ordered by the RLM for the invasion of Britain (Operation Sealion). It was a massive wooden glider that could carry either 140 fully armed troops or a light AFV or a light panzer. As such, the floor of the tranport section had to be reinforced which meant sluggish performance and dangerous handling. It was planned to tow 200 of these over Britain carrying over 20,000 troops and X-quantity of tanks to be used against the ill-equipped Home Guard. But only one machine flew in 1941 and lost control. It crashed in a farmer's field and sat for two weeks before being recovered. At that time Sealion was postponed indefinately. There were 2 prototypes + 98 under construction that were sawed-up for firewood! A total waste of time as the Me-321 heavy glider was adapted with captured French engines to become the Me-323 Gigant (Giant) transport suitable for the Med and Eastern Fronts. The Mammut would have been an easy target as it had to be towed to Britain by various aircraft like the Ju-90, several Bf 110s, or a Ju-52. It was perhaps a blessing in disguise that it got cancelled. Only a few photos of it exist (see below)...

http://www.wehrmacht-history.com/images/luftwaffe/prototypes/junkers-ju-322-prototype-2.jpg http://www.luftarchiv.de/flugzeuge/junkers/ju322_m.jpg