Originally Posted by
elitelite
I can't comment on wait times early in the morning at MIA, but one piece of advice - make sure to check what terminal concourse your flight leaves from. These days, UA has departures from both H and J, and each of those concourses has a separate security checkpoint.
Doesn't matter much. H/J (south terminal) are connected behind security. Just use the closest checkpoint near UA check-in.
OP, dont believe there are dedicated TSA Pre lanes open at 4am. You will have to use regular lanes but will get expedited screening
As for timing, whatever time you have posted sounds reasonable. Florida in general is busier this time of the year (due to colder weather in most of the US), but i would be surpirsed if it takes you more than 30 minutes from curb to post security.