Which of the following is a key requirement in positive control of airspace?

Continuous communications with airspace users is essential for maintaining positive control of airspace because it enables real-time coordination and situational awareness among all parties involved in airspace operations. Effective communication ensures that air traffic controllers, pilots, and other relevant stakeholders can exchange critical information, such as aircraft positions, intentions, and any changes to flight plans. This flow of information minimizes the risk of misunderstandings or conflicts in the airspace, which is particularly important in complex environments where multiple users may be operating concurrently.

Establishing and maintaining clear communication channels is crucial for ensuring safety and efficiency in airspace management. It provides a system for directing traffic, managing emergencies, and enforcing airspace regulations, allowing for a responsive approach to dynamic situations that may arise.

The other options, while related to airspace management in varying contexts, do not serve as fundamental requirements for ensuring positive control. Active electronic warfare capabilities, prior agreements on airspace usage, and ground-only control can play roles in broader military operations or strategic planning but are not core to the continuous and proactive communication necessary for real-time airspace management.