Dog Fight

That looks really cool man, I really love how you positioned the planes as well as perspective.

But, the background seems to monochromatic and plain Sepia. I would like if you added some blue sky behind the plain on the right side, and around that area. With some yellow'ish hues. That would also make the background more interesting, and how about adding hints of land on the bottom left corner? Like a harbour/beach or similar from high altitude to suggest that those guys are flying really high and give a better sense of height and depth, really subtle but still visible.

I also think, if you made the focal plain a bit bigger and making the wing and glass of cockpit have a bright shine and reflection from the light beams from the sun, which would make the plain more "integrated" in the scene as now it looks quite "pasted" in, and it would drag more attention to the plain itself with some bright spots and higher contrast between dark and light.
About the back aeroplain, if you'd give it a very small Guassian/motion blur, it would help a little on adding depth and speed into the image. As it looks too sharp for being at a distance like it is. Would be slightly out of focus.

And one last thing. how about making the front plain have some thick black smoke coming from the engine, with bullet holes more or less covering the plain and giving it an "beat up and abused" look like if it's been really shot up to pieces by the guy behind it?

Keep it up man, looks great so far and I'm sorry for a lot to read here. <img src="e.deviantart.com/emoticons/let…" width="15" height="15" alt="" title=" (Lick)" />