Which airspace class is described as the most restrictive, where ATC separates all traffic?

Which airspace class is described as the most restrictive, where ATC separates all traffic?

• A. Class G
• B. Class B
• C. Class C
• D. Class A - most restrictive; ATC separates all traffic

Answer: (D)

Class A airspace is the most restrictive because every operation must be conducted under IFR and under continuous ATC control, with ATC providing separation for all aircraft. VFR flights aren’t allowed in Class A except in emergencies, which makes it the least permissive. Surrounding classes (B and C) are controlled and require clearances, but they do not mandate ATC separation for every flight in the same blanket way as Class A. Class G is uncontrolled, so ATC separation isn’t provided there.

Class A airspace is the most restrictive because every operation must be conducted under IFR and under continuous ATC control, with ATC providing separation for all aircraft. VFR flights aren’t allowed in Class A except in emergencies, which makes it the least permissive. Surrounding classes (B and C) are controlled and require clearances, but they do not mandate ATC separation for every flight in the same blanket way as Class A. Class G is uncontrolled, so ATC separation isn’t provided there.