Is it possible to change Player Flight Speed?

So, I just spend about 40 minutes researching about this, and honestly, I don't know what to do.

I tried for hours to make something in MCreator but it doesn't work, and the Flight Speed does not change.

I think there's an attribute to change Flying Speed but it doesn't seem to work..

I don't know if it's possible, but if someone knows a functional way to do it, I'd highly appreciate it if they could teach me, because default Minecraft Flying Speed is too slow for what I'm planning on my superhero mod.

Characters like Superman for example, will require a higher flying speed.

Thank you for your time.