There was a lot of interest in those when all the info came to light about 19 years ago (Aviation Week and Space Technology, June 1992). It was also picked up by other consumer science magazines.
The principle was sound but the limitations were numerous. You didn't have to deal with induced drag (drag associated with making lift), there wasn't any. You still had parasitic drag but that is MUCH lower than induced. High speed possible with MUCH less thrust required (no induced drag) BUT you were limited to a maximum altitude of 1/2 the wingspan. Go higher and induced drag is suddenly back with a vengeance. You could carry a REALLY heavy payload with small engines and small fuel flow. In most cases, all the engines were used for takeoff and getting out of the water, them MOST were shut down. Unless you were willing to make a truly HUGE one, you were still at risk of large ocean waves. Unless you were willing to make the worlds largest "highways" for them, you can't really go inland. The highway wouldn't need a surface per se, but would have to have a gentle slope and clear of trees, buildings and hills. Can you imagine trying to flatten a pass through the Rockies down to near sea level and a mile or two wide?
