This week, the Department of Defense released a comprehensive 168 page "roadmap" report laying out the future of its drone program.
The DOD also released its public unmanned aircraft inventory (as of July 2013), revealing that, alltogether, the Defense Department 10,964 drones. You can see more in this chart below:
The report is mostly forward-looking, however. Here's a rough visual roadmap for aerial drones, including little birdlike craft and "nano" devices:
There are similar inventories and projections for the less-discussed ground and maritime drones, of which there are a varied many:
The report is written in fairly accessible language — well, most of it — so give it a look here. It's a revealing, and strange, look at how the United States military plans to project power, and conduct warfare, for the foreseeable future.