Hello again, class. This series of 300-level classes will be dealing with the structure of airspace. This particular article will be about airspace stratums. While most everyone is comfortable thinking in terms of lateral boundaries depicted by almost any chart, air traffic control must be thought of in three dimensions.
This is a companion discussion topic for the original entry at https://www.avweb.com/features/say-again-15atc-301-airspace-stratums