The aviation industry is facing a critical challenge in achieving carbon net-zero by 2050, with assumptions about sustainable aviation fuel (SAF) and the limitations of electric and hydrogen propulsion being questioned. While SAF is currently viewed as the primary contributor to decarbonization, concerns over its availability have prompted calls for a more radical approach. Researchers and startups are advocating for the industry to embrace new technology, challenging the notion that electric and hydrogen propulsion are only viable for short flights in small aircraft. Aviation think tanks like Bauhaus Luftfahrt have presented scenarios that emphasize the need for aggressive increases in SAF production, alongside the development of more fuel-efficient aircraft designs, to accelerate decarbonization. These scenarios also explore the potential impact of revolutionary kerosene-fueled aircraft and the gradual introduction of hydrogen propulsion after 2050. In contrast, Europe's Alliance for Zero-Emission Aviation (AZEA) envisions a greater role for electric and hydrogen propulsion, with ambitious scenarios projecting significant emissions reductions in short- and medium-haul flights by 2050. Startups like Elysian and Whisper Aero are challenging traditional beliefs by developing larger, longer-range electric aircraft, aiming to address a substantial portion of aviation emissions. The push for a more radical approach has energized the industry, with startups exploring innovative solutions to reduce emissions and improve sustainability. By reimagining aircraft designs and propulsion systems, these companies are striving to make a lasting impact on the aviation sector's carbon footprint.