It is liquid fueled. I believe it is powered by hydrogen peroxide spayed on a catalyst inside a combustion chamber on each wingtip. It's like having a bombardier beetle on each end.

Yes, but that was many many years and dead children ago.

The tip-jet helicopter plans were more of a Popular Science thing. For example Nov 1988 page 141:

http://books.google.com/books?id=ZZLk-jN3PnkC&lpg=PA141&pg=PA141#v =onepage&q&f=false

PS sometimes had the vacuum cleaner hovercraft ads, but they were definitely a Boys' Life regular. Google Books finds the same ad with the same picture running from at least 1974-2007. The later ones have a URL but it's squatted now.

Boys' Life Dec 1974 page 81 has both the big hovercraft and the tabletop one, suitably filed under "gimmicks":

http://books.google.com/books?id=OY93yymeqxQC&lpg=PA81&pg=PA81#v=o nepage&q&f=false