This is a client-side fabric mod that rotates the camera while turning during elytra flight. It's both realistic and cool since it uses actual physics to imitate the way an airplane would roll to make maneuvers.
Note: This does not in any way change how elytra flight actually moves the player or how your client interacts with the server.
New in version 1.5: Many config options have been added to realistic mode, as well as the ability to yaw/roll with strafe keys while flying, so all three axes of rotation can be used at once. Holding sneak swaps the roll and yaw input methods as before, and this can now be inverted in the config.
New in version 1.4: A new flight mode has been added, which expands upon the original concept by entirely removing the concept of up. Laterally moving the mouse controls roll rather than yaw (except when shift is held), and pitch isn't stopped by facing straight up or down, so you can do things like loops and barrel rolls. It's kind of like an actual plane. This does not replace the old behavior, rather, a setting has been added that allows switching modes between then new (Realistic) mode, old (Classic) mode, and disabling the mod for vanilla behavior. Keybinds have also been added to quickly switch between these modes.
Credit to Motschen for the MidnightLib config menu bundled with the mod.
Config options:
Mode: Selects the flight mode. 0 disables the mod and reverts to vanilla behavior. 1 is the classic roll mechanic from 1.3. 2 is the new realistic flight mode.
Turning force: Controls the sensitivity of the rolling. Higher values make the rolling more extreme, lower values make it closer to normal. Default is 1.25
Roll smoothing: Smooths out changes to the roll angle. 0 is no smoothing, 1 stops rolling entirely. Between 0.6 and 0.9 is recommended, values closer to 1 are more noticeable than lower values. Default is 0.85
Swap roll and yaw: By default, the mouse controls roll while strafing controls yaw, and holding sneak swaps this. This option inverts the shift key behavior.
Roll/Yaw/Pitch sensitivity: Multiplier for the sensitivity of mouse inputs while flying in realistic mode. Default is 1.
Key roll/yaw sensitivity: Relative strength of rotational force applied while a strafe key is held. Default is 1 for roll, 2 for yaw.
Key roll/yaw momentum: How long it takes rotation to come to a stop after strafe key is released. Default is 1.
Key roll/yaw speed cap: The maximum angular velocity achievable with strafe keys. Default is 40 for roll, 15 for yaw.
I do not plan to make a forge port, since forge is continuously becoming less popular for the newer minecraft versions that this is intended for.