How to make airship?

I'm thinking of the one in Tale Spin, a battlecruiser sized aircraft that can sustain flight.  Some helium tanks may be needed        inside the craft, protected enough not to suddenly burst or catch flame.  And propellers might help.     

Air ship sucks, period.  It is nothing but a big and slow target.  Best way to kill your enemy is to build cheap, fast and small object with lots and lots of explosive.