In the video associated with the demo here:
http://www.mathworks.com/matlabcentral/fileexchange/26123-fly-a-747-using-matlab

There was a teaser posed in the video asking why the 747 in the animation did a 360 flip at certain points in the trajectory. The answer was: We were not using quaternions.

This demo uses the quaternion functions from the Aerospace Toolbox to resolve this paradox.

Also, to add realism to the scene, the terrain was modeled in Blender, a free 3D tool for authoring powerful 3D scenes:

http://www.blender.org/

The tutorial that was referenced for creating the mountains is available here:

http://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/Mountains_Out_Of_Molehills

Use the Export to VRML feature to bring into VRML format and add the aircraft from the Objects library in VRealm Builder editor.

The sky was modeled as a half-hemisphere with texturing.

The trajectory tracing was done by creating spheres dynamically using the PROTO declarations.