Which type of operations does not require any additional seats beyond the number of jumpers?

Mass Operations are characterized by a large number of jumpers simultaneously exiting the aircraft, typically from a single jump point. In this type of operation, the arrangement and coordination allow all jumpers to be effectively accommodated without the need for additional seats. The jumpers can be prepared and positioned in a manner that maximizes the use of available space without excess seating.

In contrast, other operations like In-Flight Rigging Missions, Over the Ramp Operations, and Combat Equipment Operations often involve additional considerations such as rigging operations or specialized equipment that might require extra seated positions to facilitate preparation or management of the jumpers and their gear. Therefore, Mass Operations stand out in this context as the option that does not necessitate extra seating arrangements.