The pursuit of advanced aeronautical systems is intrinsically linked to the development of next-generation materials that transcend the limitations of conventional alloys and composites. This chapter addresses this imperative by exploring the paradigm-shifting role of nanomaterial-based fibers, a class of materials where the strategic integration of nanoscale constituents like carbon nanotubes, graphene, and boron nitride nanosheets into fiber matrices yields unprecedented property enhancements. Moving beyond mere weight reduction, the discussion centers on how these fibers impart synergistic multifunctionality, combining exceptional specific strength, superior thermal resilience, and tailored electrical properties to critical aeronautical structures. The chapter provides a critical examination of synthesis pathways, structure-property relationships, and emergent applications, from lightweight airframes to intelligent thermal management systems. It also confronts the pivotal challenges of scalable manufacturing, economic viability, and nanomaterial dispersion uniformity that currently gate widespread adoption. Ultimately, this examination confirms that nanomaterial-based fibers are poised to fundamentally reshape the landscape of aeronautical engineering. Their integration promises to catalyze a new generation of aerospace vehicles, characterized by unprecedented levels of efficiency, intelligence, and longevity. These advanced materials provide the foundational toolkit for constructing airframes that are not merely lightweight but which actively contribute to vehicle performance through embedded functionalities, setting a new benchmark for what constitutes a high-performance structural material.