There's only one flight, on AA. It leaves LHR at 11am, arriving at Raleigh Durham at 2:30. I was surprised to see RDU as my connection back to DC, but was quite happy once I arrived!
There were only 8 immigration desks, I was 5th in line for US citizens and through in less than 5 minutes. Around the corner there was one baggage carousel, re-checked around the corner, and I was back through security in 10 minutes.
Woot!