What are the vertical limits of class A airspace?

Class A airspace is defined by its vertical limits, which are set to ensure safe navigation at higher altitudes. The vertical limits of Class A airspace extend from 18,000 feet mean sea level (MSL) up to 60,000 feet MSL. This range is significant because it is where most commercial jet traffic operates, and it requires specific air traffic control services and procedures, including the use of instrument flight rules (IFR).

This airspace classification aims to separate high-altitude traffic from other airspace classes, maintaining a safe environment for aircraft movement. By requiring pilots to operate under IFR and maintaining communication with air traffic control, Class A airspace contributes to the organization and safety of air travel in the busy skies above 18,000 feet. Other ranges listed do not encompass the designated limits for Class A airspace, making them incorrect.