sorry for the late reply, but just got home from work and felt the need to reply. it seems to me that such questions are not really asked. "what if the airbus/747/strat/blimps/etc should drop out of the sky?" IMO the risk is assumed with acceptance of the technology. if the goodyear blimp should malfuction and have to crash land, manned or unmanned, i dont think would make a difference. if a blimp should become heavier than air it will drop like a stone. nothing anyone can do but pray, and considering they are allowed to fly over stadiums filled with 60,000+ people, again, it seems to me risk is assumed with acceptance. IMO