[sbalea]

To your first point, you cannot operate a commercial airliner from a carrier, for a multitude technical reasons. That being said, I seem to remember that, back in the day, the Navy would post ships at various remote points in the Pacific ocean to be there in case airliners had to ditch. To your second point, yes, to some extent it would be more efficient to make refueling stops, but you need conveniently located airports, and all those landings and takeoffs add to the duration of the flight and to the stress on the airplane, so it has to be balanced.