They come with bases and stems.
My advice would be to go ahead and glue everything together. If you must make it removable, I would glue the stem to the base instead of the VTOL. The base just isn't deep enough to properly hold the mini up loose, it'd be falling out all the time. Either way, you're probably going to have issues with the VTOL spinning on the base, unless you replace the stem with square tubing.