[fnordfnordfnord]

>With respect to airplanes forming some sort of mesh network, consider the bandwidth requirements throughout this link.

Right, but all that is really necessary is groundspeed, altitude, and equipment number. That gets you enough information to find a crash / forced landing site quickly, and to know where to search for wreckage. So, even for those parts of the flight path that are "dark" It still may be potentially superior to low-bandwidth satellite links.