Planes kept by Steven Spielberg (5)
I believe the answer is:
evens
'planes' is the definition.
(I've seen this in another clue)
'kept by steven spielberg' is the wordplay.
'kept by' indicates a hidden word.
'EVENS' is hidden within 'steven spielberg'.
(Other definitions for evens that I've seen before include "Odds that win identical sum as the stake" , "decreases" , "Balanced odds" , "Odds on something very likely to win" , "Level betting" .)