With regard to the Twin Towers, they effectively assume the non-existence of many tons of aluminum in the form of the airplane fuselage and wings, subject to melting, evaporation, leading to combustion or condensation. Nano-scale spheres of aluminum would be expected to condense from aluminum vapor. And iron is known to oxidize at environmental temperatures, let alone combustion temperatures (e.g., as the fuel in "orange" sparkler fireworks). It's all the same chemistry.
With regard to the Twin Towers, they effectively assume the non-existence of many tons of aluminum in the form of the airplane fuselage and wings, subject to melting, evaporation, leading to combustion or condensation. Nano-scale spheres of aluminum would be expected to condense from aluminum vapor. And iron is known to oxidize at environmental temperatures, let alone combustion temperatures (e.g., as the fuel in "orange" sparkler fireworks). It's all the same chemistry.