I just discovered this new technique using Ravager Launchers. Basically, if you are facing the direction opposite of what you would normally face to use a Ravager Launcher, and then use your elytra either right before or right after the Ravager launches you, you will get RIDICULOUSLY massive momentum, being able to travel 10,000 blocks vertically or horizontally very fast.
Just make sure you have unbreaking 3 on that elytra for a long journey or you might end up a splotch on the floor...