In Legacy Console Edition, sprinting flying (either in Creative Mode or with flight enabled in Survival) will move the player at a much faster speed in the direction they're looking. Currently, this isn't part of the mod.

I'm not sure how this would work with keyboard & mouse players if this were implemented, but for controllers it helps to get around (and to feel more like legacy console.)
This could also pose some challenges on servers, where it could potentially trigger an anticheat.

That... is the only place I didn't look. Sorry!

You can see on the Legacy4J main page (Modrinth, CuseForge and GitHub README) that this is already a planned addition