Hi Susano! Everybody has their comfort levels. Me, I've found getting out of Houston (I come from Ohio) means running like hell, and praying (previously) we weren't snowed in Ohio. Snowed in a couple times, this year included. This year I had to do a mad dash to Continental for their second flight (no luck, already full) then to Taca. Oh well, the joys of travel! Just a hint here....not that you probably will need it this time of year as we are past the snow...but, in the case of a delay, zoom right over to the first low client desk you see of your airline, and ask them how they plan to reschedule you. You should be on the manifest, as they do try to get you out. If not, ask them to put you on. These flights are tightly booked out of Houston and Miami, and if you stand in the line of 50 people, you will very likely spend a night there, because they won't get to you in time to get you out. Just a bit of advice from a former airline employee who has learned to sprint!
Re Belize....given possible delays up North, what works for me is just getting the ticket when we get there. Unlike the big airlines, unless something has changed since March, there is no penalty for that. Tropic and Maya, as I recall, alternate. One on the hour, the other on the half hour, so you can jump and go. And the lines have never been long, to my view, at least. Or, if you want to book ahead, do it, or get a deal from a travel agency, do it. Again, unless something has changed since March, no penalty for a change, so you will be fine if you get there late and have to make a change.