Our analysis indicates that continuing to improve technical and operating efficiencies and making greater use of biofuels can eliminate 40% to 70% of projected 2050 CO2 emissions, although these are ambitious targets that will take concerted efforts to meet. Even the best case for technical and operational efficiency improvements—including bullish estimates for bio-based sustainable aviation fuel (SAF) adoption—leave a shortfall of 30% to 60% in 2050 between projected…