This is my quick render of your scene: All fine, I just had to replace the background and adapt some materials because of the missing maps.
When watching the render result, make sure that you watch it in it’s original size. My guess is that your monitor uses a very low resolution, so in fact you did not zoom in, but rather out to see the full image, hence the artecfacting on the edges.
Some additional remarks:
The last vertex in the front is not lying on the plane’s center line, that’s why you get that gap in the nose of the plane with the mirror modifier. And if you’re rendering on the CPU you should IMHO lower the tile size. GPU rendering = large tile sizes / CPU rendering = small tile sizes.
