Originally Posted by
LessO2
Dulles is the easiest airport when it comes to clearing Customs and re-connecting.
After your friend re-checks his/her bag(s), he/she will go through TSA screening, and the exit is an escalator that empties into the C Concourse.
I flew back to the US from LHR, on 3/21. After the trek to the customs area, I was through within two minutes. However, I was using Global Entry. Since your friend is not using Global Entry, you might suggest that they see if they can purchase Economy Plus on the UA flight to IAD. This will put them farther forward, so they can exit the aircraft faster....