Which type of airport is limited to unscheduled operations of large air carriers?

The category that encompasses airports limited to unscheduled operations of large air carriers is indeed Class IV Airports. These facilities are designed with specific regulations and limitations that restrict their operations primarily to unscheduled or charter services rather than regular scheduled commercial flights. This classification helps ensure that the operational capacity aligns with the type and volume of traffic the airport is equipped to handle.

In contrast, Class II Airports typically support both scheduled and unscheduled operations but are also more equipped and designed for larger volumes of air traffic compared to Class IV, thus offering a broader range of services. Options such as Shared-Use and Joint-Use Airports serve different operational purposes. Shared-Use Airports allow multiple carriers or entities to use the same facilities, while Joint-Use Airports typically involve some level of collaboration between military and civilian operations, focusing on maximizing efficiencies rather than limiting to unscheduled large carrier operations.