It's no secret that aircraft contribute to harmful emissions like road-going vehicles, and the Environmental Protection Agency is one step closer to keeping that pollution in check. It recently finalized findings showing that some aircraft produce air pollution that contributes directly to climate change. As a result, the EPA is now free to set standards for aircraft emissions that help the US honor the Clean Air Act and, ultimately, its commitment to the Paris climate change agreement. While the US is already backing an international standard, this gives it the chance to demand tougher (or at least, more America-specific) requirements.