I've done some decaling now, so here are my impressions...
The decals are very thin and opaque, and loosen up quickly after a brief dip in room temperature water. I used Mr. Mark Setter, and they were easy to position and snugged down into the panel lines nicely. The Avrocar is finished with Alclad Aluminum, and the carrier film between letters on the U.S. AIR FORCE and other lettering disappeared completely into the background. The thinness does make them fold rather easily, so care is needed when sliding them off the backing and positioning them.
The only problem is that the red on my sheet is badly out of register. There are several red lines which are printed with a white background (for opacity), and the white background and red line are out of register by about half the line width. This is likely a random problem, but it's very annoying nonetheless.
Other than the out of register problem, I'm very pleased with the Fly decals.
Peter