Mike,
WW2 USN CV decks were stained blue during the period you want to model your Wildcat.
The stain faded very quickly in sunlight and with the wear of constant flight ops,
the wood color would begin to show through the stain.
You can use one of the bases Ed suggested, I'd select a blue one, not a natural one,
or make a base using a weathered wood tan deck blue.
I hope he enjoys your gift.
Cheers,
Mike