What is the altitude range for Class A airspace?

Class A airspace extends from 18,000 feet mean sea level up to and including 60,000 feet mean sea level, which aligns perfectly with the altitude range of FL180 to FL600. This airspace is designated primarily for high-altitude enroute operations and is intended for use by aircraft operating under instrument flight rules (IFR).

In Class A airspace, all aircraft must operate under IFR, and pilots are required to have the appropriate ratings and certifications to navigate safely within this airspace. The provision for such a specific altitude range is due to the need for effective air traffic control and to maintain safe separation between aircraft traveling at high altitudes, which is critical given the volume of traffic and the complexities of high-speed high-altitude operations.

The other options presented fall short of representing the correct range for Class A airspace, either not reaching the required starting altitude of 18,000 feet or extending beyond the upper limit of 60,000 feet. Understanding the altitude classification for various types of airspace is essential for navigating and operating safely and legally within controlled airspace.