I don't understand the reason to to that. The "flight module" is as big as an airplane, so you can't keep it as part of the car. You have to store it just like a regular airplane, and if you have to do that, why not just have a regular airplane? It would be cheaper, better suited for flying, and you wouldn't have to molest your Elise. And how did the designer choose the Lotus twin-turbo V8 to power the propellor? Just to make it more expensive? Or because it's not as cool if it doesn't say "Lotus"?
Now if you could make it dual-purpose without having a huge piece of harware that you would have to store somewhere, that would be something. Like the Aquada, which converts on the fly from a reasonably competent road car to a reasonably competent jetboat.