I have also seen proposals with blimps and even kites which make use of the wind for power and to stay up.

The mesh would have gaps, though in many cases planes go the same places ships want to, though the wind patterns at sea level are of course different from those at 30,000'. For many, intermittent connectivity, especially with a known schedule, can be very useful, if not of course as useful as full time connectivity. Combined with satellite, it can also be useful -- low bandwidth use like e-mail with no attachments and text-based surfing via satellite, and high bandwidth usages when the mesh is up. And for those for whom satellite is just too pricey, intermittent connectivity is much better than no connectivity. You just know when to make your phone calls and do your sessions. It's how we used to live in the old days.