Final answer:
The basic building block used in joint force planning and deployments of air and space expeditionary forces (AEF) is the Air and Space Expeditionary Tasking Order (AETO).
Step-by-step explanation:
The Air and Space Expeditionary Force (AEF) uses a document called the Air and Space Expeditionary Tasking Order (AETO) as the basic building block for joint force planning and deployments. The AETO is a planning document that outlines the specific missions, tasks, and resources required for a deployment. It provides guidance for the allocation of forces, equipment, and support to meet the operational requirements of the AEF. The AETO is essential for efficient and effective planning and execution of air and space expeditionary operations.