Suggestion:

Planes, pretty self explanatory, now I don’t know if this is posible but it would be nice to have, although they can be used to grief there can always be prevented blocks, for example not letting planes carry TNT or cannons, maybe only dispensers for turrets?

The plane could also be made so that it can be easily taken down.

Reasons:

First of all that way you can have an actual airforce plus it’d also be nice to be able to move around outside of the water.

Problems:

It could be abused but that could be sort of easily fixed, for example, they don’t work over claims or have many restricted blocks to prevent abuse from attacks from the air.