Maritime. The problem for both of them is range and energy density of batteries compared to oil based fuel. That is a problem, when you want to cross oceans or similar distances with planes.

There are a lot of cases in the maritime enviroment, where you do not need to cross an ocean and it is economically sensible. Currently a big one are ferries. Those are relativly short routes, with known port infrastructure. So it is easy to charge the ferries in the ports and then make the journey. The next ones in line would probably be feeder ships. Those are smaller vessels transporting cargo from smaller ports to larger ones. In the large ports they then are loaded on ocean liners. Cruise ships are also a market to watch. For Europeans style crusises it is very common to only be on sea for a night or maybe a day, to then go to a port and dump the tourist on some city. Should be possible to go electric.

For aviation it is also not nothing. There are short flights as well. Again islands are a common one. There are also things like agricultural planes, which can be electrified or say medical helicopters or maybe even fire fighting planes. However there is a lot more competition from land based transport, such as high speed rail.