two different "color topics" come together here
for the aircraft, in that time period, you'd have Gloss Sea Blue overall, with the white insignia,,,,,,okay, easy enough
then, for the ship,,,,,,maybe go with the "blue pigment shortage colors"? from here
http://www.modelwarships.com/reviews/reviews.html
just click on a palette, when it loads, click on it to enlarge it,,,,,,,you're looking for "1944 Neutral colors"
another option is to use FAA colors (colours) for your aircraft,,,,,,,,Extra Dark sea Grey, Dark Slate grey,,or whatever,,,,,,,,,and the British roundel
just some ideas
Rex