My logic was more from an insurance perspective related to a point you brought up - re: transportation improvements will likely be related to population dense e

My logic was more from an insurance perspective related to a point you brought up - re: transportation improvements will likely be related to population dense environments. Looking at the quad copters I have some doubts regarding navigation and/or performance during a catastrophic failure where others might be put at risk. That's not an unreasonable concern for life and property. As you noted, again, there are high thresholds regarding crew and passenger parameters. I think those also extend to functional operations. For commercial aviation, there is a good 50+ years of accident records and ways that companies have paid out for tragedies and whatnot. Adding in a new component - the quad copter model - is most definitely outside of the norm and I think will be viewed as high risk at first, even if there are great financial rewards to be reaped down the line pending success.