Next, we need to do a little more tidying up of the vertices…

…and a little bit more…

...and finally just a little bit more, so we can get a better look when we finally apply the Mesh Smooth modifier at the end of this tutorial.

Now, let’s move our attention to the back of the airplane. Select the polygon at the back of the model and delete it.

Select the rim edges of the just deleted polygon and Shift + Move the backwards. Don’t forget to scale them along the X axis from the top view.

Create and attach the little tail wing in the same way we did earlier with the big one.

Go back to the Edge select mode and elongate the back and a little bit more.

Target weld couple of vertices to get a smaller number of segments in the back and create the polygons that are missing.

Create the upper part of the tail and cut it down the middle with a Slice Plane.

Select the polygon as in the picture (at the bottom of the upper tail we just created) and cut it the middle.