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.
Heavy bombers are bomber aircraft with the greatest bomb load carrying capacity and longest range of their time. They have also typically been among the largest size aircraft in contemporary military or civil service.