Its a good piece but feels flat, definitely could help to use more contrast in your colors. The perspective in the back just feels off, maybe you should widen out your horizontal stabilizers a bit. The only aircraft I've ever seen with perfectly straight wings is a bi-plane, where there is two sets of wings on both sides, mounted one atop the other, I've never seen it on a single-winged plane. Even if you decide not to go through the trouble of making the wings curve back, it would probably help at least to taper back the ends instead of having that popsicle-stick shape.