I agree that planes are not likely to be electrified in the near future with current tech. Not sure about marine though.

Ships benefit from the square/cube law: square the hull area -> the volume is cubed.

E.g. if you double the size of a ship, the drag increases 4x but it can carry 8x the weight.

So larger ships are more efficient than smaller ones (at carrying containers/bulk/etc at scale).

Here in northern Europe, we already have electrified car carrying ferries etc.

Ocean going vessels will take longer though.