Common Sense

I really enjoy reading stuff like this. To me it is common sense to take advantage of all the small and relatively simple ways to increase efficiency. Getting a 3 to 5% increase in efficiency with moveable winglets would quickly add up to a very significant fuel savings (and operating cost reduction) for the airlines.  

Along the same lines of this is the research I saw about adding 'skirts' to the trailers of transport trucks which greatly improved their fuel efficiency as well.  Compared to redesigning engines, drive-lines, and fuels, this is a very simple and effective modification that could quickly pay for itself.