Adding Firework-Like Elytra Boost

Hi All! I'm new to MCreator and am trying to make a mod that adds an item that functions like a firework rocket and increases the player's speed when gliding with an elytra. I've managed to make everything work except the boost itself. I can't find a way to affect a gliding player's speed. Is there something I'm missing or is this not something that can be done in MCreator?

Thanks in advance for your help.