Crossword Genius

Inconsistent directions for one in flight - hopefully? (2,3,4)

Ross

I believe the answer is:

up and down

I'm a little stuck... Click here to teach me more about this clue!

'inconsistent' is the definition.
(I've seen this before)

'directions for one in flight hopefully?' is the wordplay.
I cannot really see how this works, but
'one' could be 'an' (an apple is one apple) and 'an' is found within the answer.
This explanation may well be incorrect...

Can you help me to learn more?

(Other definitions for up and down that I've seen before include "throughout" , "Resembling a switchback" , "Directions taken by mountaineers" , "Thus fluctuating" , "Where Puck took lovers" .)

I've seen this clue in The Independent.
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