Holds are a standard procedure for managing traffic flow into an airport and maintaining safe separation between aircraft. These racetrack-shaped flight patterns allow aircraft to be held at different altitudes while the pilot awaits further instructions from air traffic control (ATC).

The airspace network works a bit like a busy road system, but in three dimensions. When severe weather rolls in, aircraft must be safely managed around it. That pushes more traffic into other parts of the network, creates bottlenecks and reduces the number of aircraft that can safely pass through at once.

Air Traffic Controllers, or ATCOs, are closely involved in every stage of airspace change. Their operational insight is critical from the outset, highlighting risks and challenges early in the process. They then work alongside airspace modernisation teams to develop practical, innovative designs grounded in both data and real-world controlling experience.