While flying in creative mode Java edition, you cannot sprint while flying and have to sprint and then fly rather than just sprinting while flying, this doesn't happen with bedrock edition, I tested both and can confirm that there is a difference, java doesn't allow sprinting while flying, but bedrock does. 

How to reproduce

Start by creating a new world in java edition and change the gamemode from survival to creative, then try and sprint while flying.

Then create a new world in bedrock edition, change gamemode to creative and try and sprint while flying.

You will notice that bedrock allows you to sprint while flying but java doesn't.

Observations: Difference between bedrock and java being that bedrock allows you to sprint while flying and java doesn't.

Expectations: Java should allow players to sprint while flying rather than having to sprint and then fly to actually sprint while flying.