surely a stream of ionised gas would move it in a vacuum? isn't that simply action/reaction? how a regular rocket works, after all...
its definetly not science fiction or magic.. its just something which no one has taken the time to scientifically categorize.which of cource makes it mysterious and fun to the average joe blow like me.
thrust requires something to push against, which at least in my mind seems to indicate that it would be useless in a total vacuum.
even space isnt a true vacuum which is why vehicles in space can use propellent,ion discharge etc...
i did some further "research" into these devices and according to an interview in wired magazine, tests performed by nasa in a near vacuum failed to yield motion, but those tests also deprive the unit of some of its key operating elements, including air, which is used as the dielectric between the corona wire and the aluminum sheet.. so who knows..
its all for fun!
Now if they built a fully self-contained unit ("portable" 30KV generator that is lifted by the lifter) that'd be something.
indeed, the inability to produce enough thrust(if thats applicable) to carry its own power supply is indeed the tombstone of impractibility, but ive seen to pretty damn nice miniature HV DC power supplies out there with a stamp of about 1.5" 2" x .5" weighing in pretty damn light. but still the capacitors would be the killer.
a disposable camera flash charging circuit is capable of discharing up to 10kv, and weighs well under a pound.but sadly its only pulsed, but could make it jump,completely self contained... so power supplies could some day be available with light enough components.
I dont see this becoming practical anytime soon , this is just mad science fun..
oooh and its dangerous too

always a plus