if ti one freighter, which i think it is because having more will surely attract attention. Therefore they probable had one helicopter and Naomi crashed it. They might go by boats, which is a lot more quiet than helicopters - obviously.
I think they might have another chopper ???? but if the Losties see the sun setting from their camp then they puts them south west ? west island so the boat be N NE of island
I say they may have another one because when Jack was on talking to them they said something like "we have the coordinates be there soon" how soon is the question because if by boat they would then need to hike on foot to the cords....