I doubt if the fuel saving from this device will be any better than the old fashioned roof mounted wind deflector.
The reflector was fine if heading directly into the wind, but otherwise it wasn't very effective.
Perhaps the new design Aerotec might find a market for future owners of EV's which need to increase their range rather than to save fuel?
Atif, you might benefit from a factory tour around Bailey or Swift, both leading UK caravan manufacturers.
Get in touch with them to outline your ideas, Good luck!