The situation with a lot of the cities in Central and South America is that they are served by one flight a day from US gateway cities. The airline wants to use one plane a day to do the outbound and return flights. That means that US departures tend to be morning flights. If you are coming from the west coast to get to say Houston, and have a three+ hour flight AND lose two hours heading to the central time zone, a 7 am departure from LAX gets you in to Houston at 12 -- add in another 45 minutes for a legal connection, and your international connecting flight is probably long gone by 12:45pm. I just checked. For tomorrow the earliest non stop out of LAX leaves at 8:50 am. So the earliest connecting flight out of Houston would have to depart at about 2:35 or later.
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