It's neat!

I'm not sure what else to say since it's a character and it doesn't need to look photo realistic or to conform with the standards of "high art" profiles...although it's getting there. I think Ink's suggestions will go a long way to help. I'd add that if you want it to be more realistic, that you should really try to nail down the complex contours of the fuselage and nacelles. I think they're fine as is but you've got your detail down pretty good and fine tuning the shapes, both shadows and highlights, will make it that much better.