What is the abbreviation for the National Airspace System?

The National Airspace System is abbreviated as NAS, which stands for National Airspace System. This system encompasses the airspace over the United States, along with the rules, procedures, and facilities necessary for the safe and efficient operation of aircraft within that airspace. Understanding this abbreviation is crucial for anyone involved in aviation, including drone operators, as it refers to the framework governing flight operations and air traffic management.

The other options represent different entities within aviation and meteorology, such as the National Transportation Safety Board (NTSB) and the National Weather Service (NWS), but they are not related to the terminology of the airspace system itself.