you're cast shadow is far too strong. There's lots of clouds in the sky so there would only be a soft shadow really. yellows are too strong as people have noted.
To light this:
get rid of your normal lights and get your HDRI levels into a ballpark range for this shot. I'm talking about ambient levels. So you should have no direct light only ambient. Try to get that to "sit" into the background first. It will be tricky as you are not using the HDRI for that background which would help a lot. If it takes a while to render then make 3 nurbs spheres one with a white ambient material, one with a mid grey and one with a dark grey. Use them for lighting and try to sit them in the scene before you start with the plane. I start every shot with those 3 balls and a consistent set of shaders. If you can get the balls right then it will be much easier to do the plane. I guess I should really get some tutes done on this kind of stuff... when this film is over I will
As for your uvs, why did you do them with a big seam right down the top middle of your model? Wouldn't it be better for you to have the seam along the wing edge where it's less noticeable? Just a thought.
Technical Director - Framestore
Currently working on: Your Highness