In integrating space and higher altitude operations (HAO) into European ATM, there is a need to assess and mitigate performance gaps between current communication, navigation and surveillance (CNS) capabilities and HAO-specific requirements. Barometric altimetry is unreliable above flight level 600, so non-barometric altimetry solutions must be identified. SCAN builds on CNS infrastructure studies and flight trials from the ECHO2 project, aiming to: (a) propose feasible technical components and services for diverse vehicles operating in higher airspace; (b) engage airspace users, ANSPs, industry and aviation authorities to ensure operational acceptability and benefits; and (c) support the development of standards and regulatory frameworks to enable European pioneer initiatives in HAO.