What does Class A airspace primarily consist of?

Class A airspace primarily consists of the airspace from 18,000 feet up to Flight Level 600 (FL600). This designation is crucial for managing air traffic at high altitudes, where commercial airliners and other aircraft operate in a structured environment under instrument flight rules (IFR).

In Class A airspace, all operations must adhere to specific regulations, and only IFR flight operations are permitted. This is intended to ensure safety and efficiency in some of the busiest airspace regions, particularly over congested areas.

It is important to note that Class A airspace is not typically associated with lower altitude airspace, uncontrolled airspace, or restricted areas surrounding airports, which are covered by other classifications of airspace such as Class B, C, and D. Thus, the correct understanding of Class A airspace is foundational for pilots and air traffic controllers in navigating high-altitude environments safely and effectively.