These are not vehicles. These are a technology that allows a portal from light-years away. Probably, any aliens cannot actually visit, but they can interact through the portal.
My clue was when the Galectic Federation — their name for themselves — mentioned we should not be told of their existence until we understood what ‘space, and spaceships’ are.
They are portals.
One minute they’re looking for a parking orbit, then BAM! they hit an unseen portal and find themselves zooming over Arizona groping for the Undo button.