Player stops moving instantly when they stop flying in Creative mode

Please clarify what you mean by "not smooth".

When you stop flying in Creative mode it has a Sudden stop. It stops the player flying all together.

When you stop flying in Creative mode it has a Sudden stop. It stops the player flying all together.

This is working as intended. Flying mechanics were changed in the Better Together update to be similar to Legacy Console Edition.

Minecraft Xbox One/Win 10/Android Beta - 1.2 Build 9 – Minecraft Feedback