The nose of the aircraft is too dark and the eye is drawn away from it. Plus the port engines are almost indistinguishable from the port wing due to their both being too dark.
Lighting is bad and the wings are cut off! Should have taken the shot from the other side as the sun light would have reflected off the aircraft much better making the shot more dramatic!
Far too much headroom in front of the aircraft thus making the composition unbalanced.
I think Dave really hit it precisely. I personally don't have issue with wings cut off, but placing the sun behind the pic as opposed to in front would have really increased the contrast and color depth here. One more thing, the little row of cumulus at the bottom of the cloud cover look a bit unrealistic. In truth, I think there's a lot to like in this pic. The scenery is great, and the overall aircraft perspective creates a nice mood. With lighting changes and a bit of weather modifications, this would be an even better pic. :)