> The aerodynamic benefit of flying in ground effect is fairly small It's small compared to regular flight, but it's far more efficient than a regular boat hul

> The aerodynamic benefit of flying in ground effect is fairly small It's small compared to regular flight, but it's far more efficient than a regular boat hull pushing the water. A lot of that efficiency is achieved in hydrofoil mode, but lifting into ground effect mode should be even more efficient than hydrofoil (albeit as you say at some loss of stability). There are already several electric hydrofoil pleasure boats available that have remarkable range, i.e. Navier and Candela.