Quick reference

Airspace classes at a glance: A, B, C, D, E and G compared

What are the differences between Class A, B, C, D, E and G airspace?

Class A (18,000 feet MSL to FL600) is IFR only. To enter Class B you need an ATC clearance; to enter Class C or Class D you need two-way radio communication established with ATC first. 14 CFR 71.33 14 CFR 91.135 14 CFR 91.131(a)(1) 14 CFR 91.130(c) 14 CFR 91.129(c) Class E is the remaining controlled airspace and needs no clearance or radio contact for VFR, and Class G is uncontrolled airspace; both still have VFR weather minimums. AIM 3-2-6 AIM 3-3-1 14 CFR 91.155(a)

US airspace classes compared (typical dimensions; each area is individually charted)
ClassWhere it isTo enter (VFR)EquipmentPilot certificateVFR minimumsSource
A18,000 ft MSL up to and including FL600IFR only, with an ATC clearanceTwo-way radio, Mode C transponder, ADS-B Out (1090 MHz)Instrument rating (IFR flight)Not applicable 14 CFR 71.33 14 CFR 91.135 14 CFR 91.225(a) 14 CFR 61.3(e)
BSurface to 10,000 ft MSL, in layers around the busiest airportsATC clearanceTwo-way radio, Mode C transponder, ADS-B OutPrivate pilot, or a student pilot with a Class B endorsement3 SM, clear of clouds AIM 3-2-3 14 CFR 91.131 14 CFR 61.95 14 CFR 91.155(a)
CSurface to 4,000 ft above the airport: 5 NM core, 10 NM shelf from 1,200 ftTwo-way radio communication establishedTwo-way radio, Mode C transponder, ADS-B OutNo specific certificate3 SM; 500 ft below, 1,000 ft above, 2,000 ft horizontal AIM 3-2-4 14 CFR 91.130 14 CFR 91.155(a)
DSurface to 2,500 ft above the airport, around a towered airportTwo-way radio communication establishedTwo-way radioNo specific certificate3 SM; 500 ft below, 1,000 ft above, 2,000 ft horizontal AIM 3-2-5 14 CFR 91.129 14 CFR 91.155(a)
EControlled airspace that is not A–D: from the surface, 700 ft or 1,200 ft AGL, or 14,500 ft MSLNothingMode C and ADS-B Out at and above 10,000 ft MSL (not within 2,500 ft AGL)No specific certificateBelow 10,000 ft MSL: 3 SM, 500/1,000/2,000; at or above: 5 SM, 1,000/1,000/1 SM AIM 3-2-6 14 CFR 71.71 14 CFR 91.215(b)(5)(i) 14 CFR 91.155(a)
GSurface up to the overlying controlled airspaceNothingNone required by the airspace—Day, 1,200 ft AGL or less: 1 SM, clear of clouds (more at night and higher) AIM 3-3-1 14 CFR 91.155(a)

Controlled and uncontrolled airspace

Classes A, B, C, D and E are controlled airspace, where ATC service is provided to IFR flights and to VFR flights according to the class. Class G is the airspace not designated as any of them. AIM 3-2-1 AIM 3-3-1 Meeting the clearance or radio requirement before entering Class B, C or D is the pilot’s responsibility, and it stays yours even while you are receiving radar advisories. AIM 3-2-1

Class B

Class B surrounds the busiest airports, generally from the surface to 10,000 feet MSL, and is shaped in layers, some like an upside-down wedding cake. An ATC clearance is required regardless of the weather. AIM 3-2-3 A student pilot may fly solo in a Class B area only after ground and flight training in that specific Class B area and a logbook endorsement dated within the previous 90 days. 14 CFR 61.95(a) At some primary airports, such as Atlanta, Boston Logan, Chicago O’Hare and Los Angeles, you may not take off or land unless you hold at least a private pilot certificate. 14 CFR 91.131(b)(2) AIM 3-2-3

Class C

Class C usually has a 5 nautical mile core from the surface to 4,000 feet above the airport and a 10 nautical mile shelf from no lower than 1,200 feet up to 4,000 feet above the airport. A procedural outer area, normally 20 nautical miles, is not charted. AIM 3-2-4 If the controller answers your call with your call sign — even “(call sign), standby” — communication is established and you may enter. If the reply does not use your call sign, you may not. AIM 3-2-4

Class D

Class D generally extends from the surface to 2,500 feet above the airport elevation around an airport with an operating control tower, and you must establish two-way radio communication before entering. AIM 3-2-5 14 CFR 91.129(c) Where the tower is part time, the surface area becomes Class E or Class G when it closes; the Chart Supplement says which. AIM 3-2-5

Class E and Class G

Class E transition areas begin at 700 feet AGL inside a magenta vignette or 1,200 feet AGL inside a blue vignette on the sectional; surface-area Class E starts at the ground. AIM 3-2-6 Unless designated lower, Class E covers the 48 contiguous states and Alaska from 14,500 feet MSL up to but not including 18,000 feet MSL, and all airspace above FL600; federal airways are Class E from 1,200 feet AGL up to but not including 18,000 feet MSL. 14 CFR 71.71 AIM 3-2-6 Class G fills the space below the Class E floor. No clearance or radio contact is needed, but the VFR weather minimums in 91.155 still apply. AIM 3-3-1 14 CFR 91.155(a)

Speed limits that go with the airspace

  • Below 10,000 feet MSL: 250 knots indicated airspeed. 14 CFR 91.117(a)
  • At or below 2,500 feet AGL within 4 nautical miles of the primary airport of a Class C or Class D area: 200 knots, unless ATC authorizes otherwise. 14 CFR 91.117(b)
  • Beneath a Class B shelf, or in a VFR corridor through Class B: 200 knots. 14 CFR 91.117(c)

Common mistakes

  • Entering Class B because you are talking to approach or have radar service. Class B needs an ATC clearance; contact alone is the Class C and D rule. 14 CFR 91.131(a)(1) AIM 3-2-1
  • Entering Class C or D after a reply that did not include your call sign. Without your call sign, communication has not been established. AIM 3-2-4
  • Assuming Class E starts at 1,200 feet AGL everywhere. Near many airports it starts at 700 feet AGL, and around some it starts at the surface. AIM 3-2-6
  • Treating Class G as rule-free. It needs no clearance, but the VFR weather minimums and speed limits still apply. 14 CFR 91.155(a) 14 CFR 91.117

Quick answers

Which classes of airspace need a clearance to enter?

Class A (which is IFR only) and Class B. Class C and Class D need two-way radio communication instead. 14 CFR 91.135(a) 14 CFR 91.131(a)(1) 14 CFR 91.130(c) 14 CFR 91.129(c)

How high does Class D airspace go?

Generally 2,500 feet above the airport elevation, charted in MSL. AIM 3-2-5

Can a student pilot fly in Class B airspace?

Solo only with ground and flight training in that specific Class B area and an instructor’s endorsement dated within the previous 90 days. 14 CFR 61.95(a)

Where does Class A airspace start?

At 18,000 feet MSL, and it extends up to and including FL600. 14 CFR 71.33

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Sources

14 CFR (2025 annual edition, as hosted on this site; current text on the eCFR) and the Aeronautical Information Manual (Basic, with Changes 1 and 2). Checked 2026-09-27.

14 CFR 71.33 14 CFR 91.135 14 CFR 91.131(a)(1) 14 CFR 91.130(c) 14 CFR 91.129(c) AIM 3-2-6 AIM 3-3-1 14 CFR 91.155(a) 14 CFR 91.225(a) 14 CFR 61.3(e) AIM 3-2-3 14 CFR 91.131 14 CFR 61.95 AIM 3-2-4 14 CFR 91.130 AIM 3-2-5 14 CFR 91.129 14 CFR 71.71 14 CFR 91.215(b)(5)(i) AIM 3-2-1 14 CFR 61.95(a) 14 CFR 91.131(b)(2) 14 CFR 91.117(a) 14 CFR 91.117(b) 14 CFR 91.117(c) 14 CFR 91.117 14 CFR 91.135(a)

Study reference only. Written by PPL Free Ground School from the current FAA regulations and the Aeronautical Information Manual, and reviewed through our AI instructional-review system — not by a certificated flight instructor. We are not affiliated with or approved by the FAA, and this page is not an authoritative source: confirm against the current eCFR, the AIM and your instructor before you fly.

Meeting a regulatory minimum is not the same as a safe go/no-go decision. Always apply safe margins for weather, fuel, night operations, performance, and cross-country planning.

Airspace classes at a glance: A, B, C, D, E and G compared · PPL Free Ground School