FAA Airspace Classes

Class A

From 18,000 feet to 60,000 feet, all over the US.

Class B

Surrounding major airports, 0–10,000 feet. Consists of multiple layers, like an upside-down wedding cake. Most restricted.

Class C

Surrounding airports with a control tower, radar, and over a specific amount of traffic. Usually 5 NM (nautical mile) radius from 0–4,000 feet, and a 10 NM radius from 1,200–4,000 feet.

Class D

Surrounding airports with a control tower. 0–2,500 feet, no specific radius, just shaped around flight patterns. Outside control tower hours, Class D airspace is Class G.

Class E

Usually it starts at 1,200 feet and goes up to 18,000 feet. Least restricted.

Class G

Uncontrolled airspace (below Class E airspace).