Aircraft operating at high altitudes face demands for anti-/de-icing and electromagnetic compatibility. Photothermal superhydrophobic surfaces offer an energy-efficient solution due to their rapid water removal, icing delay, and photothermal de-icing. However, their strong reflectivity often fails to satisfy the strict electromagnetic requirements. Herein, an adaptive frequency selective surface (FSS) is designed using photothermal superhydrophobic modular units in a patterned array as an anti-/de-icing electromagnetic window, customizable for electromagnetic wave transmission or absorption to enable both radar stealth and photothermal regulation. A geometry-electromagnetics co-design based on equal-area patterning further optimizes the trade-off between photothermal fill factor and broadband microwave transparency. The modular unit employs Co3O4 nanoneedles for efficient tip-localized solar heating and alkylthiol passivation for durable superhydrophobicity. Accordingly, the optimized module achieves a prolonged icing delay of 1328 s and rapid photothermal de-icing within 30 s under 1-sun illumination, while maintaining over 90% radar transmittance across the 2–18 GHz range. This integrated and scalable solution combines advanced thermal management and radar stealth, offering a robust approach to aerospace surface protection.