Citroen SM was definitely an innovative car in many ways. And those fender skirts helped give it a drag coefficient of 0.26, nearly as good as a Prius, in the mid-1970's!
My very first car after graduating college in 1964 was a 1962 Citroën DS. Innovative and also great riding, with its pneumohydrolic suspension. What a car! It spoiled me for my future cars for the next 55 years until I got my Clarity
There's another new Electric car design with fender skirts. Check out the video on YouTube for Lightyear One (https://lightyear.one/).
Or maybe the Clarity looked to the future for inspiration. The much-feared Romulan Warbird. Clearly the inspiration for the rear wheel ducts were influenced by the forward "wing" design of the Warbird. And the DRL's are blatant ripoff's of the rear edge of the cabin section. Wait, now that I think about it, maybe the Romulans visited Earth during the early 21st century, saw the Clarity, and...
Here's Honda's first concept Clarity FCEV. I hoped I could buy this car, but I'm satisfied with the diminished version I am now driving. You can see the concept's influence on the front of our Claritys.
Yep - here's a photo that looks just like my '54 Pontiac that I bought for $250 in the late 1960's while in college. The rear "spats" are shown installed here, but they were removable if one wanted to take them off.