The Messerschmitt Me 321 Gigant was a large German cargo glider developed and used during World War II. Intended to support large-scale invasions, the Me 321 had very limited use due to the low availability of suitable tug aircraft, high vulnerability whilst in flight, and its difficult ground handling, both at base and at destination landing sites. The Me 321 was developed, in stages, into the six-engined Messerschmitt Me 323 Gigant, which removed some of the problems with ground handling, although the payload was reduced. Vulnerability to ground fire and aerial attack remained a constant problem during operations of all variants.