Originally Posted by
Tafflyer
Last time I arrived at ATL on BA we cleared customs in the international terminal. Delta passengers were arriving there too. Like us, they were deposited land side to transfer to the domestic side for onward connections. There was such a massive queue fir the ground transportation that they called an Uber.
I am pretty sure that this is only necessary if your connecting flight is on a separate ticket with a domestic airline that only has check-in counters in the domestic terminal. Otherwise you can re-clear security right in the international terminal (there is a checkpoint right where you exit customs) and then you have airside access to all concourses. Delta has check-in in both terminals so there is certainly no need to change terminals if flying with them.
Maybe nobody was paying attention to signs and everyone went the wrong way?