Originally Posted by
SkiAdcock
UA has its own immigration/customs so usually the waits there aren't too bad. TBIT, however, all bets are off, especially as the OP notes when all the Euro flights arrive approximately at the same time.
Do place a caveat that your experience is good for U.S. citizens and permanent residents only. When my partner and I arrived from SYD, the alien line went all the way tpo the back quickly as only 3 stations were open while 6+ were open for residents (who require much less processing).