Mixture thus I found in airport (8)
I believe the answer is:
solution
'mixture' is the definition.
(solution is a kind of mixture)
'thus i found in airport' is the wordplay.
'thus' becomes 'so' ('so' can be a synonym of 'thus').
'found in' means one lot of letters goes inside another.
'airport' becomes 'luton' (London Luton Airport).
'i' inserted within 'luton' is 'lution'.
'so'+'lution'='SOLUTION'
(Other definitions for solution that I've seen before include "something involving less concentration" , "compound" , "Way out" , "may involve a certain concentration" , "you're currently seeking?" .)