What does a "NOTAM" inform pilots about?

A "NOTAM," or Notice to Airmen, is a critical communication tool that provides essential information regarding changes or hazards that could affect flight operations. This can include updates about runway closures, changes in navigational aids, or other safety-related information. The purpose of a NOTAM is to ensure that pilots have the most current and pertinent information available when planning their flights and while in operation, especially considering that such changes may occur suddenly or be temporary.

The other options, while they may provide valuable information in different contexts, do not align with the primary purpose of a NOTAM. Upcoming airshows, while relevant to pilot awareness, would not typically be considered a matter of operational safety that a NOTAM would address. Current aircraft fuel prices are not a safety concern but rather a commercial aspect and would be reported through different channels. The availability of flight instructors is related to training and not to immediate flight operations or safety. Thus, the correct choice encapsulates the function of NOTAMs in the aviation industry, emphasizing their role in promoting safety and operational awareness.