Creating Form-Guidelines Why is it doing weird curves?

[kovach.tamas]

Hi,
I've been working on an aircraft in the form environment. I am aware of some basic rules and following those helps to make a smooth surface but at this point, I do not know how to proceed. My main problem is that the highlighted surface (blue) on the image is curving back to itself and I do not know how to fix it. I tried adding/removing edges but still, it is the best look I could achieve. 
My other problem is the pleats (marked with red arrows) on the surface. I do not know how I could eliminate them.

Any advice and help are appreciated. 

Thanks in advance!

[TrippyLighting]

Can you share your model? (export as .f3d and attach to next post)

I can see that you are using a number of N-gons and that is likely causing or contributing to the problem.

[kovach.tamas]

Thanks for your quick response! Sure, here it is. (There are many canvases/planes/etc that can be ignored.)