Some ideas that sound fun:

• drop TNT like bombs

• spray harming potion to damage enemies but not the pilot (so far i've killed myself every time I've done this)

• Maybe even make explosive arrows or a rocket-enabled gunpowder charge for the shooter for a faster rate of explosive hits (maybe non griefing too, or perhaps just scorch the hit block, etc)

Thanks for the suggestion, I am always happy to get some.
big planes can drop TNT (try TNT one hand flint&steel in the second).
sprayer can spray potions.
I was thinking of adding more fire charge like weapons, but it just felt useless in my testing.
some more advenced weapons might come in the future.