Which document supplements numerous procedures and airspace usage contained in other portions of the Air Tasking Order?

The correct answer is Special Instructions because this document serves as a critical supplement within the context of air operations, providing specific guidance and details that fill in the gaps left by more general directives found in the Air Tasking Order. Special Instructions contain details on missions, airspace usage, timelines, and any specific operational directives that may vary from standard procedures. They ensure clarity and provide tailored instructions for particular missions or operational contexts, thus enhancing situational awareness and operational effectiveness among aircrew and coordinating units.

Other options do not serve the same purpose in this specific context. Supplementary Procedures for Airspace are more focused on specific air traffic management practices rather than detailing mission-specific instructions. The Air Operations Manual offers a broader overview of operational protocols but lacks the immediate mission-centric detail that Special Instructions provide. Coordinated Control Measures involve planned joint operations in the air but may not directly supplement airspace usage as effectively as Special Instructions do.