At this moment Mojang is planning on removing the ability to shoot yourself with an arrow while using an elytra. People have suggested multiple things that will allow elytra boosting without using arrows, such as using fireworks in the air that will speed up the player.

My idea is that if a player with an elytra on is in range of an end crystal (which is a 32 radius cuboid), the elytra will become charged. A charged elytra will prevent the player from losing any speed he or she has. The elytra will continue to stay charged as long is the player is in the range of the crystal.

This would make it possible to fly at great speeds while gaining height, but at the cost of requiring some infrastructure, such as end crystal highways. It would also make a dragon fight with elytra very fun.

Thank you for reading my suggestion, and please give some feedback.