Here are a bunch or prefabs I have made. Feel free to download them and use them in you own UT levels.
My bulky space ship sounds kind of dull, but I think it's cool and adds a bit of character to a UT level. If you have played my UT level called Ranger Moon this is the ship that is sitting in the lower portion of the station just above the lower room.
The UFO ship is also a cool ship that you will see in my Ranger Moon level. This one is actually the ship that is sittign in the loading dock in the large storage room.