Originally Posted by
channa
What I do know is BOS-SFO is only 9 miles shorter than BOS-ORD-SFO, so unless you really need those 9 miles, or the fare or schedule is significantly better, it's hardly ever worth travelling via ORD on this route.
No, I am not talking about doing BOS-SFO or BOS-ORD-SFO.
The issue is, why miles traveled between 2 cities given by ual.com are different when you look for award travel or rev travel.
Examples are BOS-ORD and ORD-SFO. There might be other examples as well.