Future of Flight - safe from volcanos?

I've read a few articles like this one, about how plasma gases may revolutionise aircraft design in the future. So far they've promised a lot and we haven't seen much evidence of delivery, but I'm a sci-fi fan so I'm hopeful that we'll see this technology come good in the future.

Initially, all that's promised is a reduction in drag. Apart from being good for fuel economy, this could possibly stop volcanic eruptions grounding planes. After all, what is drag other than atmospheric particles on the planes skin? If the plane is in a bubble of plasma, it could protect to from the worst of the ash particles.

The next radical idea involves the way that plasma modifies the airflow around the plane. Future aircraft designers could do away with conventional ailerons, further reducing the exposed mechanical components and improving fuel efficiency. In addition by removing the control surfaces, you have one less thing for volcanic ash to bugger up.

But the most radical and fanciful idea I've heard is that it might be possible to get rid of conventional engines altogether. If this proves possible, it would make air travel vastly more efficient, and do away with the contrails that many people find unsightly, and maybe even transform the image of flying from being the naughty schoolchild to the clean green way to go.

And if planes had no engines, no control surfaces, and a protective skin of plasma gas, there really would be very little reason to ground them for anything but the severest eruption.

I know this is all dreaming and wishful thinking, but it's fun to speculate about the possibilities.

Hmmm, I wonder if plasma would work for that jet pack I've been waiting for?