Autopath

Open the map by typing M

Press ALT and then click on the place in the map.

Choose the altitude by sliding the bar and then click on the confirm button. No need to press your flight button your character will automatically fly (or if you're riding a mount, it will automatically go). The flight will fly in a straight line to your destination without evading any obstacles or monsters. Be careful.

Put a checkmark in the circle provided for it if you want your character to stop flying once it reaches your destination.