A truly free and open internet mesh network. We are so dependent on big telecom conglomerates as an ISP that run the last mile for the internet backbone. Wireless technology is simple and ubiquitous. I surprised we haven't come up with an ingenious way to connect all of our mobile and wifi hotspots together yet.
I had an idea, while thinking of a novel idea about how a people could challenge a fascist regime if one rose to power in the USA, You could disrupt communications, then create your own network using small drones with mesh nets that are the size of a dragon fly or something.
They would need to be easy to build, fly, program, and use, and have good range for the mesh net. Then you could send out thousands which could park on trees, and be just far enough from each other to deliver good signals but be as cost-effective as possible. If one node goes out, another one flies in and takes it's place.
I think it could be even simpler. Mobile phones are everywhere. You just need a mass of them to connect by some mesh app. For instance Firechat can be setup quickly. Perhaps integrate that with your drone idea.
