Transitioning the aviation sector to synthetic aviation fuels (SAF) requires innovative catalytic processes to overcome common limitations such as insufficient activity, selectivity, and catalyst deactivation. This study presents a detailed exploration of silica-supported phosphotungstic acid (PTA/SiO₂) as a robust solid acid catalyst for propylene conversion into jet fuel-range hydrocarbons (C₈ to C₁₆) at mild reaction conditions (150 °C). The catalyst with optimized PTA loading (10 wt %) demonstrates significant oligomerization performance, achieving high selectivity to jet fuel range hydrocarbons (>80%) and propylene conversion (>90%), alongside limited aromatic byproducts formation. Compared to conventional solid-acid catalysts such as a ZSM-5 zeolite, PTA/SiO₂ exhibits significantly reduced catalyst deactivation and can be regenerated through mild thermal treatment (<400 °C). Detailed structural characterization revealed that PTA island size influences product selectivity. Increasing the PTA weight loading leads to larger active phase island sizes, with larger PTA islands preferentially producing longer-chain hydrocarbons (C₁₅₊). Raman spectroscopy confirms the preservation of the PTA Keggin structural integrity across all catalyst loadings, although perturbations in terminal W=O vibrations occur due to interactions with the SiO₂ support. Crucially, insights obtained through combined XPS/HAXPES analyses reveal significant electronic interactions between PTA and SiO2, characterized by pronounced bending of the energy bands at the interface between semiconducting PTA and insulating SiO₂. This effect generates interfacial tungsten states, which enhance localized electron mobility and facilitate proton transfer, significantly amplifying catalytic activity. Even catalysts with minimal Brønsted acidity (1 wt % PTA loading) exhibit notable turn over, emphasizing interfacial electronic modulation, rather than bulk acidity alone, as an important performance descriptor in olefin oligomerization.