Found this out friggin around with the float trick posted earlier.
Make a macro that looks like
/dismount
/logout
Put it on your action bar and jump on your flying mount.
Fly up to a safe hight and click your new macro.
You should dismount and stay floating.
Dont do this in shatt or you will just get logged out.
I actually had a horde warlock log on as an ally alt to ask my GM who was also doing this after I showed him how this was done.
:wave: