OK, most readers are too young to get that reference to the long- and deservedly-buried TV program "Voyage to the Bottom of the Sea." But the folks at DARPA have never been afraid to think out on the edges of technology. The agency does, in fact, want to find out if a single craft that can operate on the surface, underwater, and in the air is possible.
COMMENT: This is one of those things that makes us techno-geeks say, "Go for it. If it works, it will be REALLY cool." Not to mention very useful to the Special Ops gang.