Today they might finally be close to reality. A single seat drone flyer, in a pentagram format is possible -now-. (so is a triangle format, but a single motor failure= crash and burn. With a Pentagram format the control systems have a chance of staying stable long enough through a single rotor failure to manage a safe landing)
The engineering gets quite busy. The more rotors you have in the circle, the more able the craft can withstand single failures, but the weight to lift ratios decline with each added rotor, and the motor controls become more complex. My sense tells me that five is just about perfect. A single rotor failure can be dealt with. The pilot may need to lean a bit one way though

Many efforts are being made now. The motion control software today is robust, open source, and reliable. If only I were twenty years old instead of sixty I would be all over it.
I truly am a "subject matter expert" in this area. I started tuning motor control feedback loops back in the late 70s. It's one of the few topics where I could run a stand-up lecture, on the fly, no prep, dump data to the audience, and answer every question effortlessly. Anyone want to talk PID loops? ... no, I though not.

what you all probably don't understand is that motion control systems are -everywhere-. twenty years ago I was programming cameras to control a robot arm that could pick ping-pong balls out of a random bounce in mid air. Last one I did was a high speed spooling system that took large spools of a fiber and delivered them to smaller spools. The trickly part was spinning the big spool up to speed, feed the fiber into a smaller spool, cut the end on-the-fly, dump the small spool, insert another, and start over, without stopping. Why do you think toilet paper is so cheap? It's not a bunch of chinese cheap labor wrapping those rolls for you... Chip manufacturing is -stuffed- with high speed motion control. It's everywhere, but almost completely unnoticed except for the geek patrol that puts it all together.
I'm done with all that now, but it was a very very fun ride


