Pilots stuck in traffic (3)
I believe the answer is:
raf
'pilots' is the definition.
(Royal Air Force)
'stuck in traffic' is the wordplay.
'stuck in' indicates a hidden word.
'RAF' is hidden within 'traffic'.
(Other definitions for raf that I've seen before include "Royal Air Force (abbr.)" , "Airforce of Great Britain" , "It fought Battle of Britain" .)