I personally think that noon is cutting it a little too close. Due to the tighter security regulations, you should be there 1-1/2 to 2 hours prior to a flight. Miami is also a big airport, and very difficult to try to run to some gates. Many travel agents, and even some cruise lines if you book air with them, will not do anything before 2 PM. There's very high "rescheduling fees" if you have to change your flights, so your reduced rate fare might end up costing more than an original higher priced ticket. Hope this helps out.