Which agency is responsible for the regulation of the National Airspace System?

The Federal Aviation Administration (FAA) is the agency tasked with the primary responsibility for the regulation of the National Airspace System (NAS). The FAA oversees all aspects of civil aviation in the United States, including the management of air traffic control, the safety of air travel, and the enforcement of aviation laws and regulations. Its role is crucial in ensuring the safety and efficiency of air traffic operations, as it issues regulations that govern airspace usage, pilot certification, aircraft safety standards, and more.

While the National Transportation Safety Board (NTSB) investigates aviation accidents and promotes safety improvements, it does not regulate the air traffic system itself. The Department of Transportation (DOT) serves as a broader governmental body overseeing various modes of transportation, including aviation, but it does not directly manage or regulate the NAS. The Civil Aeronautics Board (CAB), which was dissolved in 1985, once regulated aspects of airline operations and safety but is no longer in existence. Hence, the distinction and specific role of the FAA make it the correct agency responsible for NAS regulation.