Sustainable Aviation Fuel (SAF) is crucial for achieving carbon neutrality in the aviation sector. Among various production methods, Fischer–Tropsch (FT) synthesis using eco-friendly syngas has garnered significant attention. Two primary routes for producing syngas for FT synthesis—Dry Reforming of Methane (DRM) and Water Electrolysis combined with Reverse Water Gas Shift (WE&RWGS)—are actively being studied. As upstream processes, these routes are evaluated for their potential to provide low-carbon syngas for FT synthesis. However, comprehensive comparisons between these two pathways are limited, despite their importance for future technology planning and decision-making. In this study, we conduct a comparative evaluation of DRM- and WE&RWGS-based SAF production systems using virtual process design, along with life cycle assessment (LCA) and techno-economic analysis (TEA), to assess their environmental and economic viability as future technologies. LCA results indicate that the DRM-based route has more than four times lower environmental impact compared to the WE&RWGS-based system. The majority of the environmental burden arises from feedstock supply (CH₄ and CO₂) and energy inputs. TEA results suggest that while the base case scenario demonstrates limited economic feasibility, future scenarios that incorporate economies of scale and policy incentives show promise for long-term economic viability.