The check in at American is very slow compared to JFK. Be prepared to wait 20 minutes. This does not include security. That could be upwards of 30 minutes to an hour.
If you're coming or going from concourse E, DON'T take the "shortcut" through concourse D. This will take you at least 15 extra minutes to get to the main terminal.
Delta staff rude. Organization is subpar. I felt more experienced than the airport employees. If you’re in a rush, good luck. TSA is slow and inconsistent.
Worst International Airport and Immigration check-in in the USA. Allow yourself as much time as possible between connections. And get Rosetta Stone Spanish before you travel here.