I recently started working with
Blender 3D, and fortunately I didn't totally flop. First I did the Peregrin Falcon (a V-22 Osprey/UNSC Pelican inspired dropship), and the I made the alien Manta Ray (sorry if it sounds cheesy but please note that I named it after designing it). I've been running into some problems texturing them, though, so they'll just be grey models for now.
Peregrin Falcon:
Manta Ray:
Also, a great resource for 3D models is
Scifi Meshes.