Least Likely Hub-Hub CPU?
What's the most difficult hub-hub CPU? Domestic hubs are SFO, LAX, DEN, IAH, ORD, IAD, EWR. (EWR/LAX,SFO is not CPU-eligible.)
There are several pairings I never/rarely fly, but based on my experiences I suspect IAH/EWR or SFO/DEN are the most challenging.
What do you think is the most difficult hub pair for clearing a CPU?