I used to say that if it appeared in Popular Science, it meant you would never see one in real life. About the only time I was wrong was when they ran an article about a "cellular telephone system". Though I haven't seen a depiction of hexagonal-shaped coverage areas in decades.
As for the fuel cells, the article said that hydrogen fuel cells were pretty much impractical, certainly with that design where you carried the oxygen around, too.
The test mule in the article is actually the Electrovair II; the first one they built was in 1963. I met the Engineer who worked on the original. I drove Corvairs until 2009. Days before we picked up the Prius, Nissan came to town with a Blue LEAF and a white converted Versa they were giving test rides in. We wisely chose to get the Prius, and watched carefully for the appearance of the LEAF. Reserved one the next April, and you all know the rest of the story.