How is time-critical information on airports and changes to the National Airspace System communicated?

Time-critical information regarding airports and changes to the National Airspace System is communicated primarily through Notices to Airmen (NOTAMs). These alerts are essential for ensuring that pilots receive timely and relevant information necessary for flight safety. NOTAMs cover a wide range of subjects, including runway closures, changes in airport operations, hazards, and temporary flight restrictions. This direct and efficient communication helps pilots make informed decisions while operating in or around affected airspace.

In contrast, FAA bulletins provide broader updates but may not be as immediate or specific as NOTAMs. Waivers refer to exceptions granted for specific regulations, rather than routine operational information. Weather advisories focus primarily on meteorological conditions rather than airport or airspace status. Thus, among these options, NOTAMs stand out as the primary resource for urgent updates that could impact flight safety and operations.