Which statement is true regarding Class A airspace rules?

In Class A airspace, only Instrument Flight Rules (IFR) flights are allowed. This is because Class A airspace typically extends from 18,000 feet mean sea level up to and including flight level 600 (60,000 feet). The primary purpose of this airspace is to provide a controlled environment for high altitude operations, which require more stringent navigation and communication requirements that IFR provides.

Pilots operating under VFR (Visual Flight Rules) do not meet the necessary criteria for flight in Class A airspace, which necessitates instrument rating and adherence to ATC instructions. This structure ensures that aircraft are safely managed within a crowded airspace where higher altitude operations often lead to complex traffic scenarios, making it crucial that only IFR operations are permitted.