In general, in the range of airspace classes from A to G the degree of separation provided steps down at each level.
Class A is the most restrictive, and VFR flight is not possible.
Class B airspace is not allocated within the UK.
Class G has the lowest service provision. Continuous air-ground communication is required for all VFR traffic in all classes of airspace except for class G. However, pilots are expected to maintain a listening watch on the appropriate frequency and announce their intentions and positions to other traffic in the area to help maintain situational awareness and avoid potential collisions.
| Airspace Classification | Flight Rules | Notes |
|---|---|---|
| Class A | IFR ONLY | - All flights subject to ATC service and are separated |
| Class B | IFR & VFR | - All flights subject to ATC service and are separated |
| Class C | IFR & VFR | - All flights subject to ATC service - IFR separated from IFR + Traffic info on VFR - VFR separated from IFR + Traffic receives info on VFR |
| Class D | IFR & VFR | - All flights subject to ATC service - IFR separated from IFR + Traffic info on VFR - VFR traffic receives info on other VFR traffic |
| Class E | IFR & VFR | - IFR Subject to ATC service - IFR separated from IFR - All flights receive traffic info if practical |
| Class F (uncontrolled) | IFR & VFR | - Participating IFR flights receive air traffic advisories - All flights receive basic service if requested |
| Class G (uncontrolled) | IFR & VFR | - All flights receive basic service if requested |