An external power assist system for an eVTOL aircraft having one or more onboard batteries includes a subsurface power source and a power transfer interface electrically coupled to the subsurface power source. The power transfer interface is movable between various positions including a deployed position and a stowed position. The power transfer interface is configured to transfer power to the onboard batteries of the eVTOL aircraft in the deployed position. The power transfer interface is moved at least partially subsurface in the stowed position.