From Popular Mechanics:
In its latest plans for the future, the Air Force envisions swapping its pilots for a fleet of versatile—and affordable—unmanned airplanes. A single UAV with interchangeable payloads could replace several legacy airplanes. Here's a look at some possible trades.
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My Comment: I am sure that these "possible trades" will pale in comparison to what will probably be developed 10 or 20 years from now.