Hard done by pilots in court, principally supporting low-flying vehicles (11)
I believe the answer is:
hovercrafts
'vehicles' is the definition.
(hovercraft is a kind of vehicle)
'hard done by pilots in court principally supporting low-flying' is the wordplay.
I cannot quite see how this works, but
'hard' could be 'h' (abbreviation used in pencil classifications) and 'h' is located in the answer.
'done' could be 'over' (both can mean completed or finished) and 'over' is located in the answer.
'pilots' could be 'raf' (Royal Air Force) and 'raf' is located in the answer.
'court' could be 'ct' (abbreviation used in road names) and 'ct' is located in the leftover letters.
A single letter 's' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?