Mechanic concerned with pilot circling end of airstrip (9)
I believe the answer is:
repairman
'mechanic' is the definition.
(thesaurus)
'concerned with pilot circling end of airstrip' is the wordplay.
'concerned with' becomes 're'.
'pilot' becomes 'airman' (I've seen this before**).
'circling' is an insertion indicator (circling can mean going around or containing).
'end of' says to take the final letters.
The final letter of 'airstrip' is 'p'.
're'+'airman'='reairman'
'reairman' enclosing 'p' is 'REPAIRMAN'.
(Other definitions for repairman that I've seen before include "Technician" , "One who makes machines or appliances work again" , "Mechanic" , "An engineer" , "Mr Fix-it" .)