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ICAO adopted the current airspace classification in 1990. The US followed suit in 1993.

But, I found this:

In case you didn't know, the U.S. had 20 different types of airspace designations prior to 1993. (VATSIM)

  • Were there really 20 classes?
  • What were they and their functions?
  • And if possible, how did they compare with the rest of the world pre-1990 in a general sense?

What I could find was the Oct 1993 issue of Flying Magazine. From which, I couldn't find the 20 classifications, just 7 old names and some changes.

The FAA order 7400.2D from 1993 includes the change, but I can't find the similar order that precedes it. The preceding document is here, but unhelpful.

Also via here we find: Transition Areas, Continental Control Areas, and Control Areas. All three are now under Class E. That brings the total to 10 out of 20.

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  • Thanks to @Pondlife for the FAA document and for checking the AOPA magazine article.
  • $\begingroup$ I can't answer the question, but maybe the original list of 20 included special use airspace? $\endgroup$
    – Pondlife
    Commented May 16, 2017 at 13:31
  • $\begingroup$ @Pondlife - perhaps, but SUA's still exist, which can bring the count back to 20. $\endgroup$
    – user14897
    Commented May 16, 2017 at 13:33
  • 1
    $\begingroup$ Yes, that's true but I wondered if it was a deliberate or accidental piece of exaggeration, i.e. include the SUAs to make the number bigger, then exclude them to make it seem like things are now much simpler. But maybe I'm over-analyzing it :-) $\endgroup$
    – Pondlife
    Commented May 16, 2017 at 13:40
  • $\begingroup$ The previous version of the order you mentioned is here, it's from 1984. I skimmed it but didn't see any convenient table that lists all airspace types, so I'm not sure where that number comes from. $\endgroup$
    – Pondlife
    Commented May 16, 2017 at 14:03
  • 5
    $\begingroup$ We need Terry for this! $\endgroup$
    – TomMcW
    Commented May 16, 2017 at 18:00

1 Answer 1


I don't claim to have a definitive answer, but started listing the airspace I recall memorizing or seeing on charts. So here's my current list:

  1. Continental control
  2. positive control area
  3. Air defense identification zone
  4. Oceanic control area (may not be USA)
  5. terminal control area
  6. airport surveillance area
  7. tower control area
  8. transition area
  9. control zone
  10. uncontrolled airspace
  11. Military operational area
  12. prohibited
  13. restricted
  14. alert area
  15. warning area
  16. caution area (1943 aeronautical chart)
  17. danger area (1943 aeronautical chart)
  18. airways
  19. airport traffic area
  20. national park
  21. wildlife refuge
  22. fire control area (became restricted as I recall)
  23. special use area
  24. laser demonstrations
  25. blast area (later warning area, now TFR)
  26. controlled airspace

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