Yes, provided you collect all the required library headers and either sources or binaries: the generated C++ still requires run time libraries and the top level driver if it's a program.
There is actually an option of flx, --bundle=dirname, which puts the generated C++ in a single directory, to make it simpler to ship the generated C++ to another platform.
This does not do a full bundle, i.e. it doesn't package all the run time support code as well. That's on the TODO list, so you could literally copy the target directory to another machine and run "make" or something and only need a C++ compiler to build it.
There's another aspect to your question: if by "use" you also mean "modify" then the current state is that Felix generated C++ is a bit hard to read. The code is "good enough" to add debugging prints but not much more. It would be good to improve this so the code is more readable.
I see that it's billed as a "C++ code generator" and as a "scripting engine".... Does it generate C++ code that I could use without Felix afterwards?