Minecraft has a vanilla glitch where moving your head in a specific up-down pattern can allow you to fly infinitely
This mod simulates those patterns automatically.

Note: Video is not made by me

Features:

1. Customizable keybind to activate flight
2. Configurable automatic flight settings.
3. Configurable (and toggleable) HUD display which shows elytra information including
   • Flight Mode (Automatic | Manual)
   • Altitude
   • Flight Speed
   • Elytra Durability
   • Autopilot destination coords and distance
4. Automatic Collision Detection Utility
5. Autopilot

How to use Automatic Mode?

Step 1: You will need to be flying in the air using an Elytra.
Step 2: Gain a bit of height; 100 blocks above ground level is recommended.
Step 3: Press the keybind (default 'right alt') to toggle Automatic Flight on.
Step 4: Enjoy!

Collision Detection Utility

The Collision Detection Utility will automatically activate when in Automatic flight mode. If an obstacle appears in front of the player, the Utility will:

• Deactivate automatic flight
• Turn the player 180° in order to avoid the obstacle
• Print a warning in chat

How to use Autopilot?

Version 1.2.0+ has a feature: Autopilot, where you can input your destination, and the mod will take you there.
Step 1: You will need to be flying in the air with Automatic Flight Mode enabled (see above).
Step 2: Enter the command /setDestination where x y z are your destination coordinates. ^{(pls note that y coordinate is not counted; it doesn't matter)}
Step 3: Enjoy!
Step 4: The mod will automatically land if 'Perform Automatic Landing' is enabled in the Config.
Step 5: To unset your current destination, use /removeDestination. To reuse your previously set destination, enter /setDestination without any further coordinates.

Config

You can access the Config in the ModMenu Config Screen. Detailed instructions are given in the sidebar for each option.