For those of you who haven't seen it yet, there's an interesting project going on at NASA, called "Autonomous Formation Flight".

Phase 1 is under way, and there are some Quicktime movies of an F-18 intentionally flying with one wingtip directly in the vortice of the F-18 in front of him. According to the article, NASA is looking for ways to use the energy in the vortices for more efficient formation flight.

The page is at http://www.dfrc.nasa.gov/gallery/mov...M-0048-01.html