Hello! Just saying...
In WW1, the Zeppelin was one of the biggest threats to Britain. They'd drop bombs all over London. So I think the Zeppelin should definately be a bombard unit. It ought to have a pretty-allright D, though, since Zep's had many turrets.
I think this new unit would work out well with the Anti-Aircraft Gun unit that was discussed a few weeks ago. The interplay of these two could be interesting.
In any case, I think it should have the best aerial bombardment of any unit until the Advanced Bomber, just for the fact that it's able to carry so much more. Perhaps also a transportation unit, but I think its range ought to be shortened. No way 6-8 would be realistic. Zeps were fairly slow compared to other craft. I think a good way to simulate this would be to keep the range at about four, but allow base-switching.