In the article from 2011 of their dual rotor design the first comment from Mike Donovan was "uhh looks a bit "tippy""
It looks like it took them several years and thousands of dollars in R&D to agree with the critics of the old design and make a more stable quad rotor platform. Aside from allowing it to be narrower I'm still not entirely sure what the trade off is by allowing the propellers to overlap but it's no doubt still an improvement in stability over the old 2 rotor design.
Providing enough lift for the stable transportation of a person is still another magnitude of difficulty beyond the small scale model. The final platform might have to look like something closer to this or a traditional quadcopter to be stable: https://www.youtube.com/watch?v=L75ESD9PBOw

There are many more energy-efficient ways to travel from one place to another ... but I doubt if energy efficiency is on the mind anyone dying to have one of these.

Wasn't there another company that is about to start production on the first hover bike? Also a better selling point would probably be a more symmetrical design.

Worth a follow-up as work continues! QUESTION TO EDITORS - What happened to another 'hoverbike' design from a little while ago? I remember it was like a motorbike frame shape with pairs of swivelling jet exhausts [like the Harrier Jump Jet] front and rear for mobility. I feel that serious stability control problems - reaction speed? - killed that one, but perhaps with ever-improving gyro controls it may be worth revisiting.
- Think this is the one you're thinking of: http://www.gizmag.com/aerofex-aero-x-hoverbike-2017/32120/ - Ed.

That looks really awesome! I'm sure it will take a while before the engineering is sorted out, and I imagine that battery technology is a huge inhibitor right now but a promising concept. Hope to be able to cover a working prototype of this at some point!

"Its flight time is determined by the weight of its payload", what 5-10 min, 10-20 min, are there no tested ranges? Ever hear of charts? More info required.

Why not just use gyroscopic stabilization instead of going with the four rotor design?

I offered a program to fully fund manufacturing and was turned down.
Thomas

I like the fold up design, put a camera on there - great for search and rescue. We just had a lost hiker in the area. A $1,000 an hour helicopter was used to locate him. Imagine a S&R vehicle driving to the suspected area, unfolding the UAS, launching it and beginning a search. You could have a second one with water (or whatever) in it once the hiker was located. Batteries would recharge at the base vehicle. GPS software would reduce pilot workload. Pretty cool.

I would go with overhead twin contra rotating rotors front and back.