Airspace Class
Last updated: April 20, 2026 · Maintained by Aviatr Editorial Team
What is Airspace Class?
Airspace class is the ICAO letter classification (A through G) that defines what flight rules apply, whether ATC clearance is required, which separation services are provided, and what weather minimums govern VFR operations in a given block of controlled or uncontrolled airspace.
| Class | IFR | VFR | ATC Clearance | Separation |
|---|---|---|---|---|
| A | Yes | No | Required | All aircraft |
| B | Yes | Yes | Required | All aircraft |
| C | Yes | Yes | Required | IFR from IFR + VFR |
| D | Yes | Yes | Required | IFR from IFR |
| E | Yes | Yes | IFR only | IFR from IFR |
| F | Yes | Yes | Advisory | IFR from IFR (advisory) |
| G | Yes | Yes | Not required | None |
How is Airspace Class used?
Every VFR pilot memorises the airspace-class table because visibility and cloud-clearance minimums, radio-contact requirements, and transponder rules all differ by class. European Class A is IFR-only — VFR flight is prohibited. Classes B, C, D surround major airports and require a clearance to enter, with ATC providing full IFR-to-IFR separation; VFR pilots receive traffic information and, in Class C, separation from IFR. Class E is controlled airspace but does not require a VFR clearance, though transponder code 7000 is required above certain altitudes. Class F provides advisory-only ATC service; Class G below the transition altitude is uncontrolled and requires the pilot to self-announce and self-separate. The class changes with altitude and location — the same GPS position may be Class G at 1,000 feet, Class E at 3,000 feet, and Class D near an airport. Flight-planning software highlights class changes along the route so pilots can anticipate each segment's requirements.