Flying is stunning (5)

I believe the answer is:

awing

I believe this is a double definition.

'flying' is the first definition.
(rare adverb, sometimes spelled a-wing)

'is stunning' is the second definition.
(to awe is to stun or astonish)

(Other definitions for awing that I've seen before include "Causing reverent fear" , "inspiring with dread" , "Creating reverence" , "Causing dread" , "producing reverence" .)

I've seen this clue in The Times.

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