Now, I'm sure it would be possible to do it with the Conceptual Modeling tools, but it could take a while.
Why not utilise some existing 3D content and import it into a family? I described that workflow in my post Contextual 3D Views - Shaded vs Rendered. Basically, you need to:
- Download a Sketchup model that you like the look of (from http://sketchup.google.com/3dwarehouse/).
- In Revit, create a New-Generic Model family.
- Import the SKP file using Import CAD.
- Make sure the resulting geometry is of an appropriate size.
- Save the family and load it into your project.
Please note that there may be copyright on these models.
So, about that Stealth Aircraft. Here is the link.