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 the answer is hidden within the clue.
'EVENS' can be found hidden inside '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" .)