Turning off Sliding/Coasting Flight in PC minecraft

Solution 1:

At the moment, there isn't any possible way to turn it off. However, I found it useful that if you tap the S key (if you're flying forwards), you can 'jerk' yourself to a stop.

I haven't heard of any mod that allows you to this sort of thing (creative flight mode restricted to a X-Z pane (unless you crouch/jump; go down/up) that handles the same to most games like GMOD (Garry's Mod). Mods such as SinglePlayerCommands had a flight-mode like this, when you use the /fly or /noclip commands, but nowadays - Flight is now similar to which of creative in the newer versions.

Solution 2:

The DaFlight lightloader mod provides a separate flying mode without the coasting.