The Economist:

SOME technologies look wonderful on paper but don’t quite make it in the big, bad world. Airships. Autogyros. Hovercraft. They all work. They even have niche applications. But they have never lived up to their promise and been widely adopted.
 So it is with ground-effect vehicles—aircraft-like machines which skim a few metres above the sea by acquiring part of their lift from aerodynamic interaction with the surface beneath. This means they use less fuel than a true aircraft while travelling faster than a ship.