Well...what do you think?  

The aircraft look very nice. Although I do not like the clouds.

Quite nice, but

- Prop blades, they are perfectly round in your case, they are too wide, make them match the perspective, the one of the plane in the background is way to small
- The plane has a leather headcap for the pilot, would suit better
- As said before, use different paits, there must be nearly 50 paints out for this bird...
- Check the cut at the tanks, there is no need to do it perfect with stuff in the background, but the pods play an important role in this pic, as they make a big part of the lighting
- In this case it´s OK, but like said before, try to use different shots of the planes themself
- Why are coulds blurred, they are in the background, they don´t pass the aircraft too fast....


What I like:
- Nice cutting except on the pods
- Position and direction of the planes is believiable
- Not too overdone

This is just my personal point of view, that´s what I am looking for, when I do stuff, or look at stuff.

Ha, Mustangs!

I like the general composition, it gives a good impression of the two planes banking, but the cutting is a bit edgy, especially on the tanks, and as has been mentioned before, the paints should have been different. If you are aiming for a WWII shot, it should have been similar (same squadron), but slightly different, if post war/modern, it should have completely different.
I do not understand why the second plane should be blurry, they are moving at almost the same speed I assume, and are both a fair distance away, so in my mind, both should have been in focus. Same is true for the clouds. I like the idea of being above the clouds, but these ones look very strange, too strange really...
I am also not convinced by the propellors, but I do like the fact that they have different positions.

Anyway, that's my input, great choice of planes, did I mention that?