What is the difference between controlled and uncontrolled airspace for drone pilots?

Controlled airspace includes Classes A, B, C, D, and E (where it extends to the surface), and operations in these areas require prior authorization before a Part 107 remote pilot may fly. Uncontrolled airspace, designated Class G, generally extends from the surface up to 700 feet or 1,200 feet AGL depending on the area, and does not require authorization for UAS operations under Part 107. Understanding these distinctions is fundamental knowledge tested on the FAA Part 107 Unmanned Aircraft General – Small Unmanned Aircraft Systems Knowledge Test.

How do you get authorization to fly a drone in controlled airspace under Part 107?

Part 107 remote pilots can obtain authorization to fly in controlled airspace through the FAA's Low Altitude Authorization and Notification Capability (LAANC) system, which provides near real-time automated approvals up to FAA-established ceiling altitudes for thousands of locations around the country. For areas or altitudes not covered by LAANC, pilots must submit a manual airspace authorization request through the FAA DroneZone portal. Authorization is required before flight operations begin, not after, as required by 14 CFR Part 107.

Why does Class E airspace sometimes start at the surface, and does that matter for UAS operations?

Class E airspace can begin at the surface when the FAA designates it to protect instrument approach and departure procedures at airports that do not have an operating control tower, as described in the Pilot's Handbook of Aeronautical Knowledge. This surface-based Class E is depicted on sectional charts as a magenta dashed line around the airport, and it is controlled airspace — meaning a Part 107 remote pilot must have LAANC or DroneZone authorization before flying there. Missing this distinction is a common error among new UAS operators, since there is no control tower providing an obvious visual cue that the airspace is controlled.

Controlled vs Uncontrolled Airspace Distinctions for UAS

One of the most fundamental concepts a Part 107 remote pilot must master is the distinction between controlled and uncontrolled airspace. Unlike a recreational drone flier who might rely on a phone app alone, a certificated remote pilot is expected to understand the full structure of the National Airspace System (NAS), read sectional charts, and make informed, legal decisions about where a small unmanned aircraft system (sUAS) may operate — and under what conditions. Getting this wrong is not just a regulatory violation; it is a safety issue that can put manned aircraft and people on the ground at risk.

The FAA divides airspace into two broad families: controlled airspace, where air traffic control (ATC) provides some level of separation services and where specific rules apply to everyone flying in it, and uncontrolled airspace (Class G), where ATC has no authority and pilots — including remote pilots — are responsible entirely for their own see-and-avoid. Within controlled airspace, there are multiple classes — A, B, C, D, and E — each with its own floor, ceiling, communications requirements, and, critically for Part 107 operators, its own authorization requirements.

The Controlled Airspace Classes Explained

Class A

Class A airspace exists from 18,000 feet MSL up to and including FL600. All operations in Class A require an IFR clearance, which effectively means sUAS operations under Part 107 do not occur here in practice. The Part 107 altitude ceiling of 400 feet AGL (or within 400 feet of a structure) keeps remote pilots far below Class A, so this class rarely affects day-to-day drone operations but may appear on the knowledge test.

Class B

Class B airspace surrounds the nation's busiest airports — think major hubs like Chicago O'Hare, Los Angeles International, or Hartsfield-Jackson Atlanta. It is depicted on sectional charts as solid blue lines and takes the shape of an upside-down wedding cake, with the dimensions listed in the format ceiling/floor (e.g., 100/SFC means the shelf extends from the surface to 10,000 feet MSL). Manned aircraft need an ATC clearance to enter Class B. For Part 107 remote pilots, prior authorization is required before operating in Class B, and that authorization must be obtained through the FAA's Low Altitude Authorization and Notification Capability (LAANC) system or through the DroneZone portal. Operations at or above the surface within any Class B shelf require this authorization.

Class C

Class C airspace typically surrounds airports with a radar approach control and a moderate level of commercial traffic. It appears on sectionals as solid magenta circles and generally consists of a 5 nautical mile (NM) inner core from the surface to 4,000 feet AGL, and a 10 NM outer ring from 1,200 feet AGL to 4,000 feet AGL (exact dimensions vary and are published on charts). Like Class B, Part 107 operations within Class C require prior authorization via LAANC or DroneZone. Manned aircraft must establish two-way radio communications with ATC before entering Class C.

Class D

Class D airspace is typically associated with airports that have an operating control tower but do not qualify for Class C. It is shown on sectional charts as a dashed blue circle and usually extends from the surface to approximately 2,500 feet AGL (the exact ceiling is charted). When the control tower closes, Class D typically reverts to Class E or Class G airspace — a fact the FAA tests frequently. Part 107 operators must have prior authorization to fly in Class D, and LAANC is commonly available at many Class D airports for near-real-time authorization.

Class E

Class E is the most extensive and arguably the most confusing class of controlled airspace. It serves as a catch-all controlled airspace that fills the gaps between the surface-based classes. Class E can begin at various altitudes: at 700 feet AGL in areas shown by a magenta vignette (shaded border) on sectional charts, or at 1,200 feet AGL in areas with a blue vignette. In some locations, Class E extends to the surface, depicted by a dashed magenta line — this often surrounds airports with instrument approaches but no control tower. Class E airspace tops out at 18,000 feet MSL (where Class A begins). Part 107 remote pilots do NOT need prior ATC authorization to fly in Class E airspace — this is a critical distinction from Classes B, C, and D. However, they must still comply with all other Part 107 rules, including the 400-foot AGL ceiling and visual line of sight requirements.

Uncontrolled Airspace: Class G

Class G is all airspace not designated as controlled — essentially everything below the floor of Class E. In practice, Class G typically extends from the surface up to either 700 feet AGL or 1,200 feet AGL, depending on the overlying Class E floor in that area. In remote regions, Class G can extend up to 14,500 feet MSL. No ATC authorization is required for Part 107 operations in Class G. This makes Class G airspace the most permissive environment for remote pilots. Even so, Part 107 rules still fully apply: the remote pilot must maintain visual line of sight (VLOS), remain below 400 feet AGL, yield right of way to all manned aircraft, and not fly over people, moving vehicles, or at night without a waiver (or without meeting the applicable remote ID and operational rules).

Why the Distinction Matters for UAS Operations

The authorization requirement that applies to Classes B, C, and D (and Class E at the surface) exists because these areas contain the highest concentrations of manned aircraft on instrument and visual flight rules. A drone operating without coordination in the approach corridor of a busy Class C airport could cause a catastrophic mid-air collision. LAANC was specifically designed to solve the bottleneck that once required manual FAA approval taking days or weeks; today, LAANC can provide automated, near-real-time authorization for operations at or below FAA-published ceiling altitudes, sometimes called UAS Facility Maps (UASFM) altitudes. Where LAANC is not available, remote pilots must apply through the FAA DroneZone at least 90 days in advance, though in practice approvals can come sooner.

Understanding the lateral and vertical boundaries of each class is equally important. Many remote pilots mistakenly assume that if they are not directly above an airport, they are in uncontrolled airspace. In reality, Class B shelves can extend up to 30 NM from the primary airport, and Class C airspace's outer ring extends to 10 NM. Flying in a suburb 8 miles from a Class C airport could still require authorization if the drone exceeds the floor of the outer shelf.

Key Numbers and Rules

Class A: 18,000 ft MSL to FL600 — practically irrelevant for sUAS but tested; IFR clearance required.
Class B: Surface upward, solid blue lines; prior authorization required for Part 107; extends up to 30 NM from primary airport (Mode C veil).
Class C: Surface to ~4,000 ft AGL, solid magenta circles; prior authorization required; inner ring ~5 NM, outer ring ~10 NM.
Class D: Surface to ~2,500 ft AGL, dashed blue circle; prior authorization required; reverts to E or G when tower closes.
Class E: Begins at 700 ft AGL (magenta vignette), 1,200 ft AGL (blue vignette), or surface (dashed magenta); NO prior authorization required for sUAS.
Class G: Uncontrolled, surface up to Class E floor; NO authorization required; all Part 107 rules still apply.
LAANC provides automated authorization at or below UASFM ceiling altitudes; DroneZone handles requests above those ceilings or where LAANC is unavailable.
Part 107 altitude ceiling: 400 feet AGL, or up to 400 feet above a structure when within 400 feet of it horizontally.

Common Test Traps

Class E does not require authorization. Many students confuse Class E with Classes B, C, and D. Remember: authorization is only mandatory for B, C, D, and surface-level E (the surface designation). Standard Class E beginning at 700 or 1,200 feet AGL does NOT require prior authorization for Part 107.
Class D reverts when the tower closes. A dashed blue circle with no control tower operating is no longer Class D — it typically becomes Class E or G. Check NOTAMs and tower hours before assuming the class.
Airspace authorization ≠ waiver. Authorization allows you to fly in controlled airspace under normal Part 107 rules. A waiver allows you to deviate from a specific Part 107 rule (such as night operations or operations over people) anywhere. These are separate processes.
Lateral extent matters, not just vertical. Remote pilots sometimes focus only on altitude but forget that Class B and C shelves extend many miles horizontally. Always check the sectional chart for the full footprint of controlled airspace.
Class G is not a free-for-all. Operating in Class G without authorization does not exempt you from any Part 107 operating rules. Remote ID, VLOS, altitude limits, and right-of-way rules still apply in full.