@Das Bruce:
Pretty good. The polycount's nice and tight, no wasted faces that I could see, and it looks like a plane
Only critiques are these:
1. It's not terribly creative. I'd like to see something more artsy. This looks like a plane, but it looks like a 20th-Century plane, and doesn't even have the lines of something modern- it feels like a cross between a Dart and a Harrier. Which isn't bad, per se, but it just doesn't have a very futuristic feel to it.
2. It's all one part, as designed. For "win", I'd like to see some greebles that could react to animation instructions. Things like engines that are obviously going to rotate and produce vectored thrust (handy for planes that can land, given Spring's current limitations) a missile model that can disappear when the weapon fires (with the new fuel tag system, this could get quite elaborate), wings that are seperate parts so that when it dies we can blow them off, and so on. In short, it meets all specifications, but isn't going to knock anybody over.
3. A very minor quibble on polycount and modeling technique:
The sections in red are where your mesh was split in ways that aren't necessary, upping the polycount when it wasn't needed. Spring, like most modern game engines, doesn't care if your mesh is "watertight"- it's not Quake

So instead of merging those fins with the body, just have them clip into it- it'll save about 16 tris.
Also, it's welded throughout, and should probably not be. There are various tools out there that will un-weld your model, and for truely professional polish, I'd suggest it with this one, as you don't have many surfaces that are even pretending to be curved. Those are the dark blemishes on the surface, btw. Otherwise, you'll end up with those blemishes in-game. FYI, I've determined that you can use a very low welding threshhold on models, and Spring's "rounding" shader still can detect that the verts are "round", which means that if you have a modeler that will let you control these things, you should make your models have a very low welding angle.