Ethanol can potentially serve as a feedstock for sustainable aviation fuel (SAF) production. This study evaluates the global land use and associated carbon implications of expanding Brazilian corn ethanol production using second crop corn. Using a global agricultural trade model, which explicitly represents second crop corn production in Brazil, this analysis examines scenarios regarding ethanol demand growth, corn supply elasticity, and trade constraints. Results show that increasing Brazilian ethanol production using second crop corn can moderately impact international prices, land-use, and greenhouse gas (GHG) emissions, especially when corn supply is highly elastic or double cropping intensifies. Under the limiting assumption of a perfectly elastic second-crop corn land response, our findings show minimal or even negative net land-use change. Focusing on land use, a life cycle analysis reveals that second crop corn ethanol can achieve lower or negative GHG emissions, primarily due to the use of feedstock grown on land already used in the same year (second crop), renewable process energy, and the substitution of soybean meal through corn co-products. These findings suggest that Brazilian second crop corn offers a low-carbon pathway for SAF production, contingent on preserving double-cropping systems and avoiding land-use change. The article highlights critical trade-offs and policy considerations for aligning climate goals with sustainable agricultural and energy systems.