Given the critical threats to aviation safety induced by electromagnetic interference (EMI), fire hazards, and icing, high‐performance multifunctional materials integrating mechanical flexibility, EMI shielding, fire resistance, and thermal management capabilities are highly desired yet challenging. Herein, a synergistic strategy is developed involving defect engineering and graphitization to enhance EMI shielding and thermal management properties of SiBCNZr nanofiber fabrics. Initially, the SiBCNZr nanofiber fabrics demonstrate excellent mechanical flexibility and intrinsic ceramic fire resistance. Furthermore, after annealing at 1400 °C, t‐ZrO2 nanograins with various types of defects are precipitated from the amorphous matrix, accompanied by the formation of turbostratic graphite C. The synergistic effects of defect engineering of t‐ZrO2 nanograins and graphitization of turbostratic C enhance conductivity and polarization loss, leading to a specific shielding effectiveness (SSE/t) of 2718 dB cm2 g−1. Additionally, the fabrics also demonstrate remarkable electrothermal conversion capability with a rapid electrothermal response. This work provides valuable insights into designing multifunctional EMI shielding ceramic nanofiber fabrics for aviation safety.