How Airspace and Cake Share Something in Common

You’re probably wondering what cake has to do with airspace and flying. You’ll see why in just a minute.

When explaining the National Airspace System (NAS) to someone, we like to use the idea that certain airspace looks like an upside-down cake. This helps paint a picture for pilots and air traffic controllers when they’re learning how airspace works. Take a look!

As you can see, not all types of airspace look like upside-down cakes, but some do. Let’s dive further into how these work and what type of flying you can do in each.

Class A: “Alpha”

Class A airspace stretches from 18,000′ MSL (Mean Sea Level) up to FL600 (Flight Level 600, which is 60,000′). If you are flying under VFR (Visual Flight Rules) conditions or in a VFR only aircraft, you will never enter Class A airspace. This is reserved for IFR (Instrument Flight Rules) aircraft only, with a few exceptions.

What about above FL600? Currently, there are no civilian aircraft certified to fly above FL600. The Concorde was originally certified up to FL600, but never flew above FL450 (45,000′) during its time of supersonic passenger travel.

Heath Aviation

Class B: “Bravo”

Class B airspace surrounds many of the largest, busiest airports in the world. You’ll find Class B airspace at airports like Atlanta, Chicago, Los Angeles, Hong Kong, and many more. This airspace is the one that resembles the upside-down cake. As you fly closer to the airport, the “shelves” of the airspace begin to lower and fall in closer to the airport.

You must get a clearance to enter Class B airspace. Controllers will give you a transponder code to squawk, such as “Cirrus 325BK squawk 4672.” This allows them to track you on radar with all of your aircraft’s information and your destination.

Sporty’s Student Pilot News

Class C: “Charlie”

Class C airspace surrounds airports that are still very busy, but that don’t see as much air traffic and large jets typically. You must have a Mode-C Transponder to enter Class C airspace, but these airports tend to be more accessible for general aviation than Class B airports.

At Class C airports, just like Class B, you will have to get clearance into the airspace from controllers. Follow the same steps as you would for Class B airspace. Class C airports tend to have less traffic than Class B, so doing pattern work or just stopping in for fuel is much simpler than the larger airports, maybe even cheaper too.


Class D: “Delta”

Class D airspace is found at airports that are not that busy, but typically service regional airline traffic. At Class D airports, the control tower is normally only open for certain hours of the day (6:00 AM – 10:00 PM). Class D airports do not have any layered airspace like B and C airspace. Controllers typically manage air traffic visually, rather than using radar at some Class D airports.

Class E: “Echo”

Class E airspace is controlled airspace that you are not required under VFR flight to talk to controllers. However, this is the most confusing airspace for people. Class E airspace is controlled in order to maintain separation from other aircraft for any aircraft on an IFR flight plan. VFR aircraft do not receive help from controllers in this airspace without requesting “Flight Following” or other assistance.

Class E airspace begins at 1,200′ AGL (Above Ground Level) except when in a transition zone for airports, where it drops to 700′ AGL. The “transition zone” is marked on Sectional charts as a gradient magenta line surrounding an airport.


Class G: “Golf”

Class G airspace is all other airspace from the surface up to 1,200′ AGL, excluding where Class E airspace exists. Class G airspace does not include any airspace occupied by Class A, B, C, D, or E airspace, but does have a couple exceptions.

On a Sectional chart, if there is a gradient blue line, like the one below, that starts out faint and becomes bolder Class G airspace extends up to, but not including, 14,500′ MSL.


This does not cover every detail about Class A-G airspace, however, a future article will break down each one into more detail.

Hopefully now you understand a little more about the six different types of airspace in the United States. Make sure to share this article with someone in training!

Heath Aviation

Join us next week for How to Read a Sectional Chart. We’ll show you what some of those confusing icons mean and how to tell the difference.

Follow us on social media and keep up with what we’re doing!

1 thought on “How Airspace and Cake Share Something in Common

Comments are closed.

%d bloggers like this:
search previous next tag category expand menu location phone mail time cart zoom edit close