They probably use those small N Numbers because there isn't enough real estate to paint a 'normal' one
I was driving home from work here in Texas one day a few years ago and saw one parked in a field just off to the right. I circled back around (as we say over here) and got to spend half an hour or so talking to the crew, then I watched it take off. They said that all their pilots were also instructors, mostly because so few people had the airship rating that they pretty much had to. It did look like fun though
I have some good pics somewhere, but they don't show the N Number. What they DO show though is the air conditioning system: it's a hose mounted behind each prop and redirecting the airflow into the cabin - maybe it's really the pressurisation system (that was a joke btw)