The Airports Council International (ACI) introduced the most comprehensive level of the Airport Carbon Accreditation (ACA) program, Level 5, aiming for airports to achieve and maintain a net zero carbon balance. This level demands a 90% reduction in Scope 1 and 2 emissions from a 2010 baseline and thorough mapping of Scope 3 emissions, along with investments in carbon removal projects. Stakeholder engagement is vital, requiring airports to drive emissions reductions across the airport ecosystem. Notable airports like Christchurch Airport in New Zealand have excelled in achieving Level 5, showcasing leadership in sustainability. Christchurch Airport's sustainability framework includes innovative projects like a solar farm to power 30,000 homes and initiatives like ground-source heat pumps and at-gate ground power to reduce reliance on fossil fuels. The holistic approach of Level 5 fosters collaboration with third parties to address emissions comprehensively, highlighting a mature understanding of carbon management and operational excellence.