LEAP 4: Landing. World War II. the Germans desperately need a big cargo plane that can carry heavy equipment to their frontline troops. the biggest plane it the German air force, it the messerchmitt ME-321, a huge cargo carrying glider. on takeoff, the 321 sits on a detachably trolley, three fighter aircraft then tow it down the runway .but even these don't have the power to get it off the ground. so engineers fit detachable rockets to providence thrust. the aircraft was so heavy, it land on a pair of skids, to spread the load over a large area. but the glider has a fatal flaw, once on the ground, it can't move; it's stranded. engineers have to not only fit it with engines, but replace the skids with permanent wheels. but a plane this heavy needs some serious suspension. the solution comes from an unexpected source. the buffers on the front of trains. it's the perfect spring to soften the landing of a 40 ton cargo plane without bouncing it back into the air. German troops simply call it "gigant", the German word for giant.