...yes indeed....the Gudermann principle could apply here, with reservations, he thought, but as he stood facing the warm wet wind on the Inishmaan runway, I wondered how he managed to sort out the initial angle of departure to obtain the Great Circle Route shown on the map. In those far off days, with that wet wind whipping round his long heavy coat and the rain dripping into his shoes, there was no GPS to give us the answer in the pink line format we take for granted today.
Was he guided by radio signals from Ireland to help him out over the wild North Atlantic to a point far enough towards America to allow him to guess his way forward towards the right part of the continent until he recieved radio signals coming at him and could follow them correcting himself as he flew?
Perhaps, once over land again, he became completely disorientated as he tried to find the radio signal he needed. Maybe he landed and slept for some time in Nova Scotia or Newfoundland, before setting off again......