Then some airports developed around sea plane ports (eg LGA).
Ah, yes. The marine air terminal. These days, with all the land based airports, the long-range planes are strictly land-based. Operating a 777 from the water would be interesting. These days, the seaplanes are mostly small things, not the massive(for the time) 70 person craft with dining rooms. It is cheaper, faster, and pleases the customer more to fly from ground-based airports with larger jet planes.
There are a few examples (SEA, iconically enough) where this can be done, but otherwise you need a land transfer on top.
I know how to solve the International Congestion problem! A new floating terminal and a new runway, 17/35 Water!
