Take a look at some of the papers on the site -

http://www.winggrid.ch/AIAA-2004-2120.pdf
http://www.winggrid.ch/AIAA-2004-2120.pdf

Since they aren't selling anything, and they are doing both real world
experiments and academic papers with plenty of data collection, I
wouldn't call them snake oil.

The effect is real. It may be too mechanically complex to be economic,
but it's more than vaporware.