During which phase are preparation of forces and setting conditions for deployment key activities?

The phase where the preparation of forces and setting conditions for deployment are key activities is the 'Prepare' phase. During this phase, military forces focus on ensuring that all necessary resources, capabilities, and plans are in place to support future operations. This involves a range of activities, including training, mobilization, logistics planning, and establishing command and control structures. The emphasis is on readiness and ensuring that forces can effectively respond to potential operational needs.

In the context of the joint air operations planning process, understanding the 'Prepare' phase is crucial as it sets the foundation for successful execution of military operations. It allows commanders to assess their forces' capabilities and determine the necessary steps to achieve operational objectives.

While the 'Deter' phase might involve some preparatory elements, it primarily focuses on discouraging adversarial actions through a show of force or readiness, rather than on the specific logistics and operational readiness required for deployment. The 'Execute' phase shifts focus to carrying out the planned operations, and the 'Assess' phase evaluates the effectiveness of strategies and actions taken. Therefore, 'Prepare' is the most fitting choice for the activities highlighted in the question.