From an engineering perspective, racing cars are much closer to aircraft than they are to road cars; they just have their wings upside-down.

With the difference that they are typically not allowed to have mobile aerodynamic surfaces.

That's why fan cars can be considered cheating. The fan is made of mobile aerodynamic surfaces. The Brabham BT46B try to circumvent the rules by saying their fan was a cooling fan, it didn't work.

If you allow mobile aerodynamic surfaces, indeed, you are going to have aircraft. It is easy to imagine a car with actual wings, with flaps, ailerons and elevators.

Not to be too much of a pedant, but the Brabham BT46B's excuse that the majority of airflow was used for cooling did stand, which was why Lauda's one race win wasn't taken away. It was protests from other teams, Ecclestone's personal interests, and rule changes after the fact that meant it only raced that one race.

Totally, but I still got downvoted a bunch... Using air for propulsion only makes sense if you're saving weight by which point you're better off cornering with wings instead of dragging wheels around with you.

These fans are to create _down_ force to increase the "weight" of the car.

Wings(/flaps/ailerons) are great for that, too, depending on their orientation. And arguably simpler. More effective at high speeds, but then apparently so are these fans.

I am very much aware. I was pointing out why using fans for propulsion would not be a good idea.