Airspace Design is the structured process of defining, configuring, and modifying the three-dimensional volumes of controlled and uncontrolled airspace in which air traffic services are provided, to meet safety, capacity, efficiency, and environmental objectives.

It encompasses the determination of airspace classifications, the geometry of control sectors, terminal areas, and controlled zones, the specification of vertical and lateral limits, and the allocation of airspace use between civil and military stakeholders.

Route Network Design is the discipline of establishing and optimising the network of published ATS routes and associated significant points across a defined airspace. It determines the horizontal and vertical alignment of airways and RNAV routes, the location and designation of waypoints, and the integration of Performance-Based Navigation (PBN) specifications that define the required navigational accuracy for each route segment.

Route Network Design operates at the interface between traffic demand, aircraft performance, navigation infrastructure. At the network level, it addresses connectivity between city pairs, cross-border route continuity, and the progressive transition from ground-based navaid-defined routes to area navigation and free route airspace environments.