But the Nigerian unit is hardly complex - got only a few feet of the
ground.

Really?

Do you *know* this?

No one on this list has seen the aircraft flying, nor a video of it
flying, nor a picture of it flying.

If a link to a legitimate new source can be found (not to a blog),
then it will at least be some evidence. As it stands now, there is no
evidence this is anything but a hoax.