Methods for large-scale additive manufacturing of high-strength boron nitride nanotubes (BNNT)/aluminum (Al) (e.g., reinforced Al alloy) metal matrix composites (MMCs) (BNNT/Al MMCs), as well as the BNNT/Al MMCs produced by the large-scale additive manufacturing methods, are provided. A combination of ultrasonication and spray drying techniques can produce good BNNT/Al alloy feedstock powders, which can be used in a cold spraying process.