The color scheme you've decided on here is in this is actually really nice--it reminds me a little of the color schemes you'd see from an artist like moebius--sort of whimsical but very beautiful. I also like the pilot's pose quite a bit. It actually reminds me of photos i've seen from the era.
That said, I definitely see a few things to work one. First, there's only really depth separating the pilot from the spitfire--in the form of the hard black cast shadow he's throwing. I think the painting could be improved a lot by a clearer separation of values. With a vista going out as far into the sunset as your painting shows, you'd expect the distant dunes and cliffs to start fading into the background due to atmospheric perspective (in this case, since the sun's going down behind the cliff, it might actually be relatively dark--but the point still stands). On the other hand, the pilot and spitfire would have lots of sharp contrasts that would help them stand out as the focal point of the piece.
I would also recommend you look into constructing a perspective grid for a piece with lots of depth like this. It's usually a pain, but it can help a lot. In particular, the spitfire feels more like a flat stamp than a large piece of crashed machinery because it's not converging onto a vanishing point (although the further broken wing does seem to point towards one).
Just a few thoughts areas to continue working on don't take anything i've said as law, it's just what jumped out at me when i was looking at your work. I know it's easy for somebody to to type out criticism but it can be darn hard to actually do the fixes. I look forward to seeing more of your stuff down the line!