This looks interesting, but what

This looks interesting, but what about ekranoplans? Have a look at the KM ("Caspian Sea Monster") and also the MPE-400, which, with a displacement of 470 tonnes, is capable of carrying 460 passengers (about the same as the latest Boeing 747s) at 500 km/h (around 300 miles per hour) in a sea swell of up to 3 metres (nearly 10 feet) at an altitude of around 5 metres (15 feet or so) for up to 6000 kilometres (and very fuel efficient with it). And if the engine conks out? no worry! just float like a boat! I want one!