Well, no offense taken, but you can't beat the laws of thermodynamics. If you try to utilize the drag over the vehicle, you will simply require more power to make it move.
What you're suggesting is just a version of the "Why not put a windmill on the top of the car to charge the battery while it's moving? " idea. It won't work- you can't get something for nothing, and you can't even break even.
Regarding the solar panel idea- this is at least feasible as a range extender, although 400 watts is not a lot of power. 400 watts= about 0.54 horsepower and I'm guessing that the electric motor on the vehicle is at least 50 horsepower so it's about 1/100 of the load. Even at 400 watts for 10 hours you're looking at enough power stored to run the car for a few minutes at best.
I hate to be a wet blanket, but there is a lot of wishful thinking involved in electric cars as a practical matter. That's the big reason whjy they have to have a huge tax credit to attract people to them.
With current battery technology, you just can't store enough power in a small enough package to get a decent range for anything but commuting, and the charge rate is so much slower than just filling a tank with gasoline, that it makes the vehicle rather impractical for anything but a round trip to work, or running around town.
If people want to buy them, then they should do so, but they need to be aware of the drawbacks.
My $0.02. YMMV