This airship flies using the Movecraft plugin. This schematic is for 1.8, if you use it in previous versions the sign text will be screwed up and will have to be replaced before flying it. The airship apears towards the end of the attached video.

Background:

The large bulk freighters are usually used to transport vast quantities of goods within the Silver Empire. Their large size and double hulled design give them tremendous carrying capacity, although it also makes them unweildy and an easy target. 

For this reason, they are usually kept far from any potential combat areas.