As flown by RAF boys? (5)

I believe the answer is:

kites

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'boys?' is the definition.
Although both the answer and definition are plural nouns, I cannot understand how they can define each other.

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for kites that I've seen before include "aircraft" , "Aerial toys; birds" , "Small hawks" , "Large hawks or flying toys" , "More than one toy" .)

I've seen this clue in the Evening Standard.

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