Mitigating aviation’s impact on climate change requires major changes in aircraft configurations and operations. Digital methodologies that optimise aircraft performance will play a key role in this transformation. Through eight industrial test cases, the EU-funded Horizon Europe NEXTAIR project will build and validate novel design methodologies, data-fusion procedures, and smart health assessment tools. Together, these solutions will lead to the digital transformation of aircraft design, manufacturing, and maintenance. The project will improve methods to better tackle the uncertainty in manufacturing and the inconsistency in operations for the industrial, multi-disciplinary design of aircraft and engine components.