Setting the legalities aside, flying any of these without the training behind a pilot's license sounds like a great way to have some fun, right up until you have a really bad day. Maybe you can skip the license---I haven't looked at those regs myself---but you can't skip the skills.<p>(I'd also want to take a hard look at the design, parts, and maintenance before I flew something like this---but I don't really have the training or experience to do that. I know some people who I might trust to do it for me, but I think they all have A&P certificates. Again, maybe you can take shortcuts & skip the expensive, highly trained mechanic, but that shortcut may not take you where you want to go.)