Ground school · Lesson 1 of 8
The National Airspace System
Area II · Airspace & Operating Requirements · 3 min read
ACS UA.II.A · 14 CFR 107.41
Six letters, one picture. Controlled airspace is A, B, C, D, E. Uncontrolled is G. There is no Class F in the United States. "Controlled" means ATC is providing separation services there - and for a drone it means you need FAA authorization before flying in it (B, C, D, and Class E designated to the surface for an airport - that's the §107.41 list).
✋ Try it
Class G
On the chart: Not drawn — it is everything under the E floors
To fly there: No authorization needed. This is where most Part 107 flying happens
Exam trap: Uncontrolled ≠ unregulated: every 107 rule still applies here
Tap each class to see its chart marking, whether you need authorization, and the trap the exam sets with it.
AGL vs MSL first
- AGL = above ground level: height above the dirt under you.
- MSL = mean sea level: height above the average ocean surface - a constant reference that doesn't care about terrain.
- Sectional charts use both. Class B/C/D altitudes chart in MSL; the Class E floors (700/1,200) are AGL; your 400-ft drone ceiling is AGL.
The classes
Class A - "Above all." 18,000 to 60,000 ft MSL. IFR only, airliner territory. Irrelevant to drones except as the top of Class E: E runs up to but not including 18,000 (17,999).
Class B - "Biggest/Busiest." The nation's busiest airports (ATL, DFW, LAX, JFK, ORD, DEN). Upside-down wedding cake, usually 2–5 shelves, typically topping around 10,000 MSL. Solid blue lines. Always towered. Drones need authorization - and the surface core is generally a no-go without a specific reason.
Class C. Moderately busy airports with towers, radar approach control, and airline service. Two-tier cake: inner core typically surface to ~4,000 MSL, outer shelf floor typically 1,300–2,100 MSL. Solid magenta lines. Authorization required.
Class D. Smaller towered airports. Surface to typically 2,500 ft above the field (charted as an MSL number in the dashed-blue box). Dashed blue lines. Authorization required. When the tower is part-time and closed, the airspace usually reverts to E or G - the chart note "See NOTAMs/Directory for Class D/E eff hrs" tells you where to check.
Class E. Everything controlled that isn't A/B/C/D. Where it starts is the whole game:
- at 700 ft AGL inside a faded magenta vignette,
- at 1,200 ft AGL in most other places (with or without a faded blue ring),
- at a specific MSL altitude where a blue zipper line says so,
- at the surface where a dashed magenta line encircles an airport - and only this surface-designated E is in §107.41's authorization list.
Class E at altitude above you is legal drone airspace (your 400-ft world usually sits under it anyway - but the 400-over-structure rule can carry you into it legally).
Class G. Uncontrolled, surface up to the overlying E floor (1,199 AGL at most). Where most drone flying happens. No authorization needed - but every Part 107 operating rule still applies: 400 AGL, VLOS, visibility, cloud clearances.
✈ Quick check
Your drone is at 300 ft AGL inside a faded magenta vignette. Whose airspace are you in, and do you need authorization?
Authorization mechanics
- LAANC (Low Altitude Authorization and Notification Capability): near real-time authorization through FAA-approved apps. The controlled airspace around an airport is divided into grid squares, each with a pre-approved maximum altitude; request at or below it and approval is near-instant. Launched October 2017; before that, manual applications took weeks.
- Where LAANC isn't available: manual request through FAA DroneZone.
- When FAA materials say "ATC authorization," for a drone that means FAA authorization via LAANC/DroneZone - you do not call the tower.
Reading it on the chart
Covered in depth in the sectional-charts lesson, but the pairing to memorize:
| Class | Line on chart |
|---|---|
| B | Solid blue |
| C | Solid magenta |
| D | Dashed blue |
| E to surface | Dashed magenta |
| E at 700 AGL | Faded magenta vignette |
| E at 1,200 AGL | Faded blue vignette, or nothing at all |
| G | Whatever's under the E floor |
The trap: no ring doesn't mean no airspace. An unmarked airport sits in Class G with Class E starting at 1,200 AGL. Airspace exists everywhere; the chart only draws the boundaries that differ from the default.
✈ Quick check
Which flavor of Class E is on §107.41's authorization list?
Phonetic alphabet
Worth memorizing - the exam and every frequency you'll listen to use it: Alfa Bravo Charlie Delta Echo Foxtrot Golf Hotel India Juliett Kilo Lima Mike November Oscar Papa Quebec Romeo Sierra Tango Uniform Victor Whiskey X-ray Yankee Zulu.
Done reading?
The read only sticks once you use it. Drill Area II while it is fresh.