The Boeing 747-400 and the 747-100 Shuttle Carrier was a job I had to built for Xplane10.
The biggest error I made in this model was in the 747-400 hump. In my model was shorten than reality, and this was not noticed by anyone until it was released. But I never fixed it as never found the time to be free of my other works in Laminar.

The fix of the hump was made by other person in Laminar. So what you can see in Xplane11 is my model with my texture of Xplane10 with the hump fixed.
Also for this model I was in charge of building the 3D Cockpit, which I was very proud of, but it was rebuilt from scratch for x-plane11. At least the 747-100 Nasa still has the old great cockpit I built and that so much energy toke.
Another thing I built was the cabin.  Something I had to take a lot of care, because the big number of seats that this plane has. Of course I didn't built the same number, because that would mean much more polygons, so worst performance in the plane. So the trick was to make the seats bigger.
If you go to one of the toilets you will see one surprice, that I was told to make....
One trick that saved me lot of time was to not connect the cabin vertex with the exterior holes of the windows. In all my models I alwasy do this, but this beast had massive number of vertex in the interior, so to save in polygons I didn't make the exterior holes for the windows. You won't be able to see from outside to inside of the cabin, but yes to the oposite. How this miracle can it be? Because in Game engines, to save performance only one of the faces of a polygon is rendered. If you look to the exterior model from inside, you won't see any polygon, because those internal faces are not rendered. That way I didn't have to connect the good ammount of internal windows to the external. I liked that solution and was proud of it!