This story is purely about a radar contact, so it's quite possible it was some sort of ECM test gone awry.
As for UFOs, the weird part is most of the stories stem from the 50s and some in the 60s then they stop. I think it quite likely there WAS some sort of visitation going on then that has since cut way back. Maybe they were passing by, spent a few years doing in depth research, then moved on. After all, we went to the Moon then left for over 20 years. We went to Mars with Viking and didn't try again for 20 years. It's hardly unusual to think that we may get "waves" of explorations. I also don't doubt many of them are UAVs...er, U-UFOs? Just probes, hence the ability to make maneuvers that would flatten a pilot.