Current aviation roadmaps are not within planetary boundaries.

Aviation decarbonization roadmaps relying on fuel substitution do not meet planetary boundaries and persistently transgress climate and biosphere limits through 2050.

• Why it matters: Understanding the systemic environmental impacts of aviation decarbonization is crucial to ensure sustainable transportation within Earth's safe operating space, beyond just climate change.
• What they did: The study integrates life-cycle inventories with planetary boundaries to evaluate the impacts of aviation roadmaps, analyzing trajectories up to 2050 across different scenarios.
• The result: Fuel-switch-centered strategies fail to achieve sustainability, requiring at least a 7.2% annual decline in air traffic and combined demand-side and supply-side governance to align aviation with planetary limits.