I have to say that the idea of wearing shorts under a skirt does not excite me. The whole reason I wear skirts is as an alternative for shorts. Skirts are cool, comfy, sexy and always look smart, even if paired with a less than smart top...just the fact that it's a skirt takes it up a notch. Wearing shorts underneath would take away the whole cool and comfortable factor for me...and it would probably put a damper on the sexy factor too.
Of course, I mostly (read: Only) wear straight skirts--so flyaways are not an issue. And even if I did flash a little thigh getting in or out of the car--I really don't care. If someone is looking, then they need to be prepared for what they might see!