The most common and most likely answer to this crossword clue is the 8 letter word COCKPITS
I've seen this crossword clue in The Daily Telegraph
C
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More clues leading to the result COCKPITS
Buddy explains!
The straight part
We know that "where flying must be controlled" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case where flying must be controlled = cockpits.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does COCKPITS mean?
COCKPITS noun- The driver's compartment in a racing car (or, by extension, in a sports car or other automobile).
- The compartment in an aircraft in which the pilot sits and from where the craft is controlled; an analogous area in a spacecraft.
- A pit or other enclosure for cockfighting.
- A site of conflict; a battlefield.
- The vagina.
- A valley surrounded by steep forested slopes.
- The area set aside for junior officers including the ship's surgeon on a man-of-war, where the wounded were treated; the sickbay.
- A well, usually near the stern, where the helm is located.
- An area from where something is controlled or managed; a centre of control.