Andy Borgogna and I went flying in the Tustin Blimp Hangar yesterday. I don't know if anyone else has flown a complete pattern inside such a place, but we did! We flew Andy's P-51 and Baby Pathfinder. Used up all the batteries for both planes, 8 flights, I think.
There are some chalenges to such flying. The overall lighting is kind of dim, and the ceiling and walls are dark, but with skylights the entire length of the building at two levels. So you are constantly flashing the model in and out of different lights. Makes keeping track of the model a trifle difficult!
In addition, the air is dead calm, so wake turbulence is a serious problem.
However, it was rewarding, as the free-flight guys and R/C guys were very interested, and happy to see a pretty unique event.
Tony Naccarato took one flight on the P-51 and really liked it!
If we didn't live here in So. CA with our great weather, we would probably fly C/L there again; however, our local park has much better lighting!