As for methods of learning, I don't think telling
them that all cars
don't fly, when there are some that do is proper. Telling them that
cars, in common practice, do not fly, yet there are some that do, is
more effective. That might challenge the student (the one who is
actually interested) to find out for themselves which cars do actually
fly, and why.
In my experience, very nearly any car can be made to fly, under the right
conditions. The roller-coaster section of I-680 near Benicia used to work
quite well for that purpose. But Caltrans has since flattened it out, so
it's no fun any more.