The poor cat is trying to enjoy a nap on the nice, smooth floor when some human comes along with some infernal machine that makes enough noise to wake the dead. Naturally he’s gonna get a puffy tail! You would, too.
Our cats fell in love with puffing out their tails, once they first learned to do it, but have since grown out of it. We’re all getting old.
Another way to tell is that the ears go back.