Airborne traffic, ultimately, still high (8)
I believe the answer is:
ecstatic
'high' is the definition.
(thesaurus)
'airborne traffic ultimately still' is the wordplay.
'ultimately' indicates one should take the final letters.
'still' becomes 'static' (static can mean still or not moving).
The last letters of 'airborne traffic' are 'ec'.
'ec'+'static'='ECSTATIC'
(Other definitions for ecstatic that I've seen before include "Jubilant" , "In religious fervour" , "Overjoyed, quite delighted" , "In a state of great delight" , "Transported by joy" .)