Pipistrel Panthera is simply the most efficient 4 seater of the world. This beast can cruise at 200 knots while consuming only 15 gal/hours.  Panthera achieves unprecedented efficiency through careful aerodynamic shaping, retractable titanium undercarriage or lightweight advanced composite structure. 
One of the main advantages of 3D printed technology is that it allows you to build complex shapes without any extra cost or time. Pipistrel Panthera is a clear example of really complex shapes.  You won't find a sharp edge anywhere, everything is smooth and elegant. For all those reasons this airplane is a great model to be 3D printed and really take advantage of this incredible new way of building RC planes.