Airspace classes describe volumes of sky with different operating requirements. For Part 107, you need prior air traffic control (ATC) authorization to fly in Class B, C or D, or within the lateral boundaries of an airport's designated Class E surface area. Class G does not require that authorization. The decisive question is which airspace contains the drone at its location, altitude and flight time. If you are organizing your exam preparation, place this airspace lesson within the Part 107 study sequence.
Being below 400 feet does not make controlled surface airspace disappear. Conversely, standing beneath an airport's elevated airspace shelf does not necessarily put a low-flying drone inside that shelf. Start with the volume, then apply the authorization rule in 14 CFR Part 107.
On This Page
- What each airspace class means
- Why the same location can have different classes
- The Class E distinction that changes authorization
- Worked examples: classify the flight first
- Common traps beyond the class letter
- Turn a correct answer into a flight decision
What each airspace class means
The U.S. classes relevant to this lesson are A, B, C, D, E and G. There is no U.S. Class F. A through E are controlled airspace; G is uncontrolled. Controlled airspace provides an environment for ATC services, including aircraft flying under instrument flight rules. It does not mean every aircraft in every controlled class needs the same permission.
For a remote pilot, learn the purpose and boundaries of each class, then use Part 107's own operating requirements. Do not substitute the radio-entry rules for a crewed airplane.
Airspace classes and their Part 107 consequences
| Class | What the airspace generally represents | Useful sectional-chart clue | Part 107 consequence |
|---|---|---|---|
| A | High-altitude controlled airspace, generally 18,000 feet MSL through flight level 600 | Not specifically depicted on sectionals | Outside routine low-altitude small-drone operations; do not treat omission from Section 107.41 as permission to enter |
| B | Individually shaped layers around the busiest airports | Solid blue boundaries and sector altitude labels | Prior ATC authorization for flight inside the Class B volume |
| C | A surface core and surrounding shelf at qualifying airports | Solid magenta boundaries and altitude labels | Prior ATC authorization for flight inside the Class C volume |
| D | Usually a surface area around an operating control tower | Dashed blue boundary, often with a boxed ceiling | Prior ATC authorization while operating in active Class D |
| E | Controlled airspace serving airport and en route functions; its floor varies | Dashed magenta for surface areas; shading or other labels for elevated floors | Authorization depends on the airport surface-area distinction explained below |
| G | Airspace outside designated controlled airspace | Determined from the surrounding boundaries and overlying floor | No Section 107.41 authorization solely because the flight is in G; other restrictions still apply |
Source basis: the FAA Aeronautical Information Manual's controlled-airspace definitions, its Class G explanation, the July 9, 2026 Chart Users' Guide, and Part 107. The final column applies those sources to small-drone flight; it is not a complete list of operating conditions.
MSL means mean sea level. AGL means above ground level. A flight level is a pressure-based altitude designation. Keep the first two references distinct when solving low-altitude airspace questions.
Why the same location can have different classes
A chart is flat, but an airspace boundary has a floor and a ceiling. A shelf is an elevated part of a controlled-airspace area. The land beneath it can have another class extending upward from the surface.
Class B and C labels normally express the ceiling above the floor in hundreds of feet MSL. A label written as 40 over 15 means a 4,000-foot MSL ceiling and a 1,500-foot MSL floor. SFC means the floor is the surface. A boxed Class D ceiling of 25 means 2,500 feet MSL; a minus sign before the number excludes that ceiling altitude. Read additional chart notes and exclusions rather than assuming every outline is a simple cylinder.
For an MSL shelf floor, put the aircraft's altitude on the same reference:
Aircraft altitude MSL = ground elevation MSL directly beneath the aircraft + aircraft height AGL.
This is arithmetic for a stated scenario. Do not automatically substitute the nearby airport elevation for the ground elevation at a different flight site.
Class E floors often use a different reference: 700 or 1,200 feet AGL. A magenta vignette, the softly shaded boundary, identifies a 700-foot AGL floor on its shaded side; other chart markings and notes define adjacent floors. A blue vignette can identify a 1,200-foot AGL floor adjoining Class G. An unshaded patch is not proof that Class G extends upward without limit. These conventions are illustrated in the FAA Chart Users' Guide, airspace information.
When two designations actually overlap in the same volume, the more restrictive class applies in the order A, B, C, D, E, G. A B shelf above a D surface area is a different situation: the classes occupy different heights until their designated volumes overlap. The FAA explains that distinction through its airspace hierarchy.
The Class E distinction that changes authorization
Class E is controlled airspace even when a Part 107 authorization is not required. Separate these three cases:
- Airport surface area: Class E designated as a surface area for an airport is the Class E case covered by Section 107.41. FAA authorization procedures identify it as Class E2.
- Surface extension: A separately designated Class E extension supporting approaches to nearby controlled airspace is not automatically an E2 airport surface area. Its dashed magenta outline alone does not establish the Part 107 authorization requirement.
- Elevated Class E: Where Class E begins at 700 feet AGL, a drone at 300 feet AGL is below it, assuming no other controlled volume occupies that location. The drone is in G under the stated conditions.
The FAA's Part 107 authorization procedures expressly limit the Class E authorization requirement to the lateral boundaries of airport surface areas, Class E2. Do not decide from a dashed line's shape whether a real location is E2 or a separately designated extension. Resolve the actual designation through current FAA airspace information and the authorization service before using the exception.
Tower hours also matter. When a part-time Class D area closes, it can revert to Class E surface airspace or Class G. The airport's Chart Supplement entry identifies the status; a closed tower does not by itself establish G. If it becomes an airport Class E surface area, the authorization requirement remains relevant. See the AIM's part-time surface-area guidance.
Worked examples: classify the flight first
These are original practice scenarios with hypothetical values, not actual exam questions or instructions for a real location. Unless stated otherwise, assume no overlapping airspace or temporary restriction. Each answer addresses airspace classification and authorization only.
1. A low flight beneath a Class C shelf
A site's ground elevation is 900 feet MSL. The Class C shelf is labeled 40 over 15. There is no other controlled airspace below the shelf. The planned drone height is 300 feet AGL.
The aircraft would be at 900 + 300 = 1,200 feet MSL. The C floor is 1,500 feet MSL, so the aircraft is 300 feet below it. With no other controlled airspace below the shelf, the answer is Class G, with no Section 107.41 authorization triggered by that class.
The trap is selecting C merely because the point lies inside the shelf's outline on the map. The floor does not reach this flight.
2. Still below 400 feet, but inside Class B
A different site has ground elevation of 800 feet MSL. An active B shelf begins at 1,000 feet MSL. The proposed height is 300 feet AGL, and the aircraft remains below that shelf's ceiling.
The aircraft would reach 800 + 300 = 1,100 feet MSL, placing it 100 feet above the B floor. This flight enters Class B and needs prior authorization. The 400-foot AGL operating limit does not override the shelf boundary.
The trap is comparing 300 feet AGL directly with a 1,000-foot MSL floor. Converting references changes the answer.
3. A magenta shaded area versus an airport surface area
Site One is inside a magenta vignette, with E beginning at 700 feet AGL and G beneath it. Site Two is inside a verified E2 airport surface area. Both proposed flights reach 150 feet AGL.
Site One's flight is Class G, below the elevated E floor. Site Two's flight is within the airport's Class E surface area and needs prior authorization. The drone height is identical; the airspace floor and designation differ.
The trap is treating all magenta markings as either automatic permission or automatic prohibition.
4. The tower closes before the flight
A Class D airport's current Chart Supplement says the airspace is Class E at other times. The proposed operation falls after the published D hours and within the airport surface area.
The applicable surface class is E, as specified. The pilot still needs the applicable airport surface-area authorization. Changing the scenario to an entry that specifies Class G would change the classification, but would not remove the duty to avoid interfering with airport traffic.
The trap is replacing the published airspace status with the assumption that an unattended tower means uncontrolled airspace.
5. A facility-map cell marked 100
A Class D site has a UAS Facility Map value of 100 feet. The desired flight is 80 feet AGL. No authorization has been issued.
The flight remains in Class D, and the map number is not permission. A request at an eligible altitude may be suitable for the authorization process, but the pilot must receive the authorization and follow its terms. The FAA explicitly distinguishes UAS Facility Map values from flight authorizations.
The trap is reading an administrative review altitude as either an airspace boundary or an approved flight ceiling.
Common traps beyond the class letter
Class G does not mean unrestricted. Part 107 still requires yielding to other aircraft and avoiding interference with airport traffic. Prohibited or restricted areas and applicable temporary flight restrictions create separate obligations. Airspace class is only one part of the preflight assessment.
Weather minimums do not become looser because the flight is in G. Under ordinary Part 107 rules, flight visibility must be at least 3 statute miles from the control station, and the drone must remain at least 500 feet below clouds and 2,000 feet horizontally from them. Do not import a crewed-aircraft Class G weather exception into a Part 107 answer. These requirements are in Sections 107.37 through 107.51.
Calling the tower is not the authorization process. FAA procedures direct Part 107 applicants to LAANC or FAA DroneZone; an ATC facility contacted directly must direct the operator to those systems. An ordinary radio acknowledgment is not a substitute for that authorization.
A diagram's dimensions are illustrative. Use the actual charted boundaries and published status. An airport's proximity, size or tower symbol cannot replace the airspace designation at the intended flight location.
Turn a correct answer into a flight decision
For a study problem, write a short answer with three parts: the class at the stated height, the boundary or designation that proves it, and the Part 107 authorization consequence. If you cannot explain the middle part, revisit the chart instead of memorizing the answer letter.
For an actual flight, use current charts, the Chart Supplement and applicable notices to confirm location, vertical limits and operating times. Check the whole intended operating area, including any segment that approaches a shelf or crosses a surface boundary.
Where authorization is required, use an FAA-approved LAANC service or FAA DroneZone as applicable. LAANC supports automated requests at participating facilities; DroneZone handles manual requests, including airports without LAANC. The FAA's airspace authorization instructions explain both routes. Receive the authorization, read its location, time and altitude limits, and separately confirm the remaining flight requirements before takeoff.
If you are new to drone aviation, use our guide to becoming a drone pilot to place this lesson in the broader training and certification process.
Sources
- 14 CFR Part 107: federal regulation covering airspace authorization, airport traffic, restrictions, preflight duties and operating limits.
- FAA AIM, Section 3-2: Controlled Airspace: official definitions, vertical structure and part-time surface-area status.
- FAA AIM, Section 3-3: Class G Airspace: the uncontrolled-airspace definition.
- FAA Aeronautical Chart Users' Guide, effective July 9, 2026: chart boundaries, ceiling and floor notation, and Class E symbols; also the source of the featured page.
- FAA AIM, Section 3-1: General: hierarchy when airspace designations overlap.
- FAA Order JO 7210.3, Section 19-6: Part 107 Operations: authorization procedures and the Class E2 distinction.
- FAA UAS Facility Maps: what grid altitudes establish and why a map does not grant permission.
- FAA Part 107 Airspace Authorizations: LAANC and DroneZone application routes.
Last checked: September 6, 2026.