How to fly on Minecraft servers?

I've been playing Minecraft for a few days out of boredom. I currently prefer to play on servers rather than alone.

Now to my question:
How can you fly on a server (e.g. GommeHD.net) on your own plot without having any premium?

You would help me a lot.

If you are creative, or you can get the rights from an admin

This is not easy because it is a significant advantage in the game.

Bed wars