Text and paths are vectors and no pixels. This means that the cmputer calculates the lines. This is really great for scaling them up and down.
But PHotoshop itself works best with pixels. A photo and also our skins simply exists of colored dots.
Now if we look at a text layer and use the transform tool, you will see that some transform options are greyed out.
Also there is no possability to select a part of the text and transform only that part.
When we have rasterized the layer (i.e. converted it from vectors to dots) we have all transform options available and also can apply the transfom on a selected part of the text.
Here I scale the upper half of the text, which is more or less what you also need to do with the Spitfire. The Distort option might be helpfull to scale one side more then the other.
Net I select the right half of the text and skew it. This also is an action you need to do to get the text right.
And finally a bit of an example how bad the text looks in the skin. But in game it will look pretty good. Look at skins from other people to see how they distorted the text to get it show right in the game. That will give you an idea about what you need to do.
In game the distorted parts will look a bit blurry, since the game itself distorts it again (that is why you need to do this all in the first place). There is nothing to change that.