I think that the software could account for the price differential. I'm going to assume that it took a lot more programming and testing to develop the software for the car controller, than it did for the plane controller. I'm not saying that the large difference in price is justified.

I compared the specs of the two controllers and they appear to be identical. I wonder if the 125 was initially designed as a car controller and then made into a plane controller as an after thought, either by accident or design.