HMM, looks great. But I have not done the tutorial, so I cant give you any real specific pointers. But I did notice the blades for the propeller are looking odd. I cant really give a 100% reason, but it seems like they are obvously nurbs or subdivs, they look very clay like in the texturing, and not very industrial looking, they look almost organic actually. Sorry I cant give you a definite problem, but I guess you could look at that as a good thing.

Good Job,
-Ryan