Which classification of airports primarily handles scheduled large and small aircraft along with unscheduled large aircraft?

The classification of airports that primarily handles scheduled large and small aircraft, along with unscheduled large aircraft, is Class I airports. Class I airports are typically significant facilities in the airport system, catering to a higher volume of air traffic and a greater variety of aircraft operations.

These airports often support major airlines and have the infrastructure necessary for large-scale commercial operations, including the ability to accommodate both scheduled services (which are regular flights determined by airlines) and unscheduled operations (which include charter flights or other non-regular flight services). This dual capability makes Class I airports crucial for maintaining connectivity in the air transportation system, serving as pivotal nodes that facilitate a robust flow of passengers and cargo.

In contrast, the other classifications—Class II, Class III, and Class IV—represent airports with varying levels of capacity and types of operations that may not offer the same comprehensive services or ability to handle all types of aircraft at the same scale as Class I airports.