Airspace from 18,000 MSL up to and including FL 600 is classified as?

Airspace from 18,000 feet Mean Sea Level (MSL) up to and including Flight Level (FL) 600 is classified as Class A airspace. This designation is significant because Class A airspace is where all aircraft are required to operate under Instrument Flight Rules (IFR), and it is primarily used for high-altitude jet traffic.

In Class A airspace, air traffic control (ATC) maintains separation between all aircraft, ensuring a safe and organized flow of air traffic. This area covers the national airspace system above a certain altitude and is critical for managing the complexities of high-altitude operations where commercial airliners frequently operate.

Understanding the classifications of airspace is essential in air traffic control, as different classes have specific rules regarding visibility, cloud clearance, communication requirements, and weather minimums that pilots and ATC must adhere to, ensuring the safety of all aircraft operating within that space.