Airspace Classification Overview

Airspace is where Part 107 candidates lose the most points, and where working pilots get the real fines. About one question in five on the Remote Pilot knowledge test is an airspace question, and nearly all come down to one decision: can I launch here right now without asking anyone, or do I need an authorization first? This lesson gives you the map to answer that in ten seconds for every class of airspace in the National Airspace System (NAS).

The One Rule That Organizes Everything

Under 14 CFR 107.41, no person may operate a small unmanned aircraft in Class B, Class C, or Class D airspace, or within the lateral boundaries of the surface area of Class E airspace designated for an airport, unless that person has prior authorization from Air Traffic Control (ATC). Everything else is detail hanging off that sentence. In one of those four places, you need an authorization (usually through LAANC, covered next lesson). In Class G, or under Class E that begins at 700 or 1,200 feet AGL, you do not.

The rule does not say you need a waiver, a permit from the airport, or a phone call to the tower. ATC authorization is a specific product, and the FAA tests whether you can tell it from a waiver under 14 CFR 107.200. Notice also that the limits of 14 CFR 107.51 (400 feet AGL or within 400 feet of a structure, 87 knots, 3 statute miles visibility) apply in every class. An authorization never lets you climb above 400 feet AGL; it only lets you fly inside controlled airspace up to the altitude ATC approves, often lower.

Class A, B and C: The High and Busy Airspace

Class A runs from 18,000 feet MSL up to and including FL600. Everything inside is IFR, and no Part 107 operation can get there, so remember only the floor: 18,000 feet MSL.

Class B surrounds the busiest airports (Atlanta, Los Angeles, Denver, JFK and about three dozen others). It is drawn with solid blue lines, shaped like an upside-down wedding cake whose layers widen as they rise, and the whole structure usually tops out at 10,000 feet MSL. Each segment carries a fraction such as 100 over 30, meaning that layer runs from 3,000 to 10,000 feet MSL. For a drone, only the segment whose floor is the surface (SFC) matters: under an outer layer whose floor is 3,000 feet MSL, a drone at 400 feet AGL is below Class B and is in Class G or E.

Class C surrounds airports with a control tower, radar approach control and meaningful airline traffic (roughly 120 of them). It is drawn with solid magenta lines. The standard shape is a 5 nautical mile inner core from the surface to 4,000 feet above airport elevation, and a 10 nautical mile outer shelf from about 1,200 feet AGL to the same ceiling, labeled on the chart in hundreds of feet MSL. The surface core requires authorization; the outer shelf, with its 1,200 foot floor, does not reach down to where a drone flies.

Class D and Class E: Where the Real Mistakes Happen

Class D surrounds smaller airports with an operating control tower but no radar approach service of their own. It is drawn with dashed blue lines, usually a circle of about 4 nautical miles, from the surface to 2,500 feet above airport elevation. The ceiling is printed in brackets in hundreds of feet MSL: [31] means up to and including 3,100 feet MSL. Many Class D towers close at night; when the tower is closed the airspace reverts to Class E or G (the Chart Supplement says which). Class D exists only while the tower operates.

Class E is controlled airspace that is not A, B, C or D. It has several floors, and only one matters for 14 CFR 107.41. A Class E surface area, drawn with a dashed magenta line around an airport, extends from the ground up and requires ATC authorization. Class E beginning at 700 feet AGL is shown by a shaded magenta vignette: the soft fading edge faces the 700 foot side (inside the band), the hard edge faces the 1,200 foot side (outside). Class E beginning at 1,200 feet AGL covers most of the country and is not drawn at all. Since you cannot fly above 400 feet AGL, beneath that Class E you are in Class G. Read the magenta: dashed means surface and authorization; shaded means 700 AGL and you are free below it. The dashed magenta extensions that stick out of some Class D circles along approach paths are Class E surface areas, and 14 CFR 107.41 applies inside them too.

Class G: Uncontrolled, Not Unregulated

Class G is everything not designated as controlled. It extends from the surface up to the floor of the overlying Class E, at 700 feet AGL, 1,200 feet AGL, or in a few remote areas 14,500 feet MSL. It has no ATC services and no authorization requirement, and most Part 107 work happens here.

Uncontrolled does not mean anything goes. In Class G you still carry every operating rule: visual line of sight under 14 CFR 107.31, the altitude, speed, visibility and cloud clearance limits (500 feet below, 2,000 feet horizontal) of 14 CFR 107.51, the restrictions on flight over people in 14 CFR 107.39, the preflight familiarization of 14 CFR 107.49, and the Remote ID broadcast rules of 14 CFR Part 89. TFRs and Special Use Airspace can sit on top of Class G, so a chart check and a NOTAM check belong in every preflight.

Worked Example

A client asks you to photograph a warehouse for sale. On the sectional it sits inside a dashed blue circle labeled [28], 3 miles from a towered airport at 300 feet elevation. Step one: dashed blue is Class D, so 14 CFR 107.41 applies and you need an ATC authorization before launch. Step two: [28] means the Class D ceiling is 2,800 feet MSL; it is not your flight altitude, which is still capped at 400 feet AGL by 14 CFR 107.51 and probably lower by the LAANC grid for that cell. Step three: a second site across town lies under a shaded magenta vignette with no dashed line. That is Class E from 700 feet AGL, so at 400 feet you are in Class G and may fly without authorization after checking NOTAMs and TFRs. Two sites, three miles apart, two different legal answers.

Exam Tips

• The FAA shows a sectional excerpt and asks whether ATC authorization is required at a marked point. Decide from the line style: solid blue, solid magenta, dashed blue or dashed magenta mean yes; shaded magenta or nothing means no.
• Altitudes printed on the chart for Class B and C segments and Class D brackets are in hundreds of feet MSL, not AGL.
• Expect the standard dimensions as answer choices: Class C 5 NM core and 10 NM shelf to 4,000 feet AGL, Class D about 4 NM to 2,500 feet AGL, Class B to 10,000 feet MSL, Class A from 18,000 feet MSL.
• An authorization is not a waiver. To fly in Class D you need ATC authorization, not a Part 107 waiver and not the airport manager's permission.
• Class G never exempts you from the 107.51 altitude, visibility and cloud clearance limits.