I read your post about your lighting. For proper lighiting total light in the scene should not add up to more than one. For three lights it would be something like 0.6 0.2 0.2. Also It would look better if your main light was changed to abient and one of the extra lights was moved to within 40 degrees of the first the third should be across from the others. Given your model is air born i would consedr having the third light below and the main lights 45 degrees above the plane to simulate sunlight and ground reflection. Also the abient light should be tinted to match the background colour. Good Luck.

Also a very transpernt repeat layer of your background above the plane layer would give the image depth. And some kind of bumb on the metals would get rid of the coloured glass thing you got going on. Mabey a very low noise or a custom map to suit whatever metal that is.