LevelFlight allows you to fly perfectly level with a key press. It does this by taking advantage of the fact that you can set your pitch limit (how much you can angle up or down) to zero, meaning you can move in a perfectly straight line while flying or swimming.
-- Bind LevelFlight to a key in the key bindings. Pressing the key will force you to fly level. Pressing it again will allow you to fly free.
-- You can also create a macro containing "/click LevelFlightButton" to toggle level flight.
-- There is a simple configuration section at the top of LevelFlight.lua.
KNOWN LIMITATION: When your pitch limit is set to zero you are unable to look up or down. You can only move your camera horizontally around your character. Turning off level flight restores full range of motion to the camera.