Describe the feature you have in mind.

config option to limit max height, prob with option to remove elytra from recipe
will move jetpack into earlier progression and keep balance

Does this solve a particular problem?

No response

Do you mean a max height above the point the player has started at, or an absolute max height in the world?

I mean height above closest block that's right below player, so for example if you hover up or down the hill, you will follow the shape of it, but like 15 blocks above