In Class A airspace, which of the following is correct?

In Class A airspace, the regulation and operation standards are strictly defined by FAA rules. The correct answer indicates that only Instrument Flight Rules (IFR) flights are permitted. This is because Class A airspace is designated for high-altitude operations, typically starting at 18,000 feet mean sea level (MSL) and extending to 60,000 feet MSL. The requirement for IFR operations in this airspace ensures that all aircraft are under the control of air traffic control (ATC), promoting safety and efficiency in a busy airspace environment.

The requirement for IFR adherence means that pilots flying in this airspace must operate under the standards of instrument flying, including filing flight plans, maintaining communication with ATC, and adhering to specific altitude and route assignments. This structured environment supports the safe separation of aircraft and enhances situational awareness for both pilots and air traffic controllers.

In contrast, the other options present scenarios that do not align with the established regulations for Class A airspace. VFR (Visual Flight Rules) flights are not allowed to operate in Class A airspace unless they are operating under IFR, which is why the notion that all types of flights can operate without restrictions is incorrect. Similarly, implying that ATC instructions might be optional