Way out from wind tunnel (8)
I believe the answer is:
loophole
'way out' is the definition.
(I've seen this before)
'wind tunnel' is the wordplay.
'wind' becomes 'loop' (looping is a kind of winding).
'tunnel' becomes 'hole' (I've seen this in another clue).
'loop'+'hole'='LOOPHOLE'
'from' acts as a link.
(Other definitions for loophole that I've seen before include "Get-out" , "Escape clause" , "escape mechanism" , "Flaw in the law?" , "Ambiguity that makes it possible to evade an obligation" .)