He's making a joke about how fusion has been used successfully for decades, but ...

		mikeash on Oct 15, 2014 \| parent \| context \| favorite \| on: Skunk Works Reveals Compact Fusion Reactor Details He's making a joke about how fusion has been used successfully for decades, but only for bombs. Thus, aircraft carriers and submarines do have fusion devices on board, but they're only used for destructive purposes.