Nitinol alloys are most qommonly known for their superelasticity and thermal shape memory [1]. The lerm 'shape-memory' is used to describe the phenomenon of restoring to a predetermined shape on heating, after having been 'plastically' deformed; 'superelasticity' refers to the enormous elasticity of these alloys.
For pilots, the definition of a large aircraft is  taken from the Code of Federal Regulations, CFR 1.1, which defines a large aircraft as aircraft with a maximum certificated takeoff weight of more than 12,500 pounds. In contrast, a small aircraft is one with a maximum certificated takeoff weight of 12,500 pounds.
Bringing the enormous aircraft to fruition is not a done deal, but it's a good sign that the incredible build is under way. Once finished, the behemoth plane will have a 385-foot wingspan, making it the largest aircraft ever. It's not designed as a passenger plane, though. Backer Paul Allen (he of Microsoft fame) has bigger plans in mind: space launches.