The only thing you need to do this glitch is the Reaper Crest.

Step 1) Get to a save point where you are not sitting on a bench (e.g. I would recommend the exit of Chapel of the Beast as it is close and makes it easy to retry if you fail).

Step 2) Go to any bench and sit down, but save and quit before sitting down fully.

Step 3) Reload the game. If you respawn while not sitting on a bench, then bench storage will now be active.

Step 4) Go to the room shown in the video and equip the Reaper Crest using bench storage.

Step 5) Go to the left of the statue and do a dash attack to the right.

Step 6) Near the end of the attack, enter the crest menu using bench storage and switch to any other crest. This will cause you to gain height at a high speed.

Step 7) This is the tricky part. Whenever you pause, your height acceleration will slow down but you will continue moving right. You need to time it so that you go high enough to be over the ledge next to the loading zone but low enough to not hit any ceilings. Pause a few times before and after you reach the required height (as shown in the video) so you can be at the perfect elevation.

Step 8) If you have done everything correctly, then Hornet should fly right and into the loading zone. Otherwise, you will be stuck and will need to save and quit before retrying the glitch from Step 4.

This works on current patch, so anyone should be able to do it :D