nice job, i assume the plane is crashing towards the guy? If so why not have a layer between the background and the plane and use a circular lined gradient to make it appear to be moving (on my website its in the tutorial). Apart from the guy running it sort of looks like the plane is standing still that's all. Another way to create motion for the plane is to actually draw some chunks of dirt and grass flying into the air where the plane has impacted. Apart from that you are doing really well.....
next week i hope to have about 75 pages on my site, i changed it a bit go have a look at the new book now.