United in fact does fly one 777 flight on that route each way but it goes the other way (DC->SF at night, SF->DC in the morning). Big planes rarely idle much.

United in fact does fly one 777 flight on that route each way but it goes the other way (DC->SF at night, SF->DC in the morning). Big planes rarely idle much. The domestic legs are generally tacked onto longer haul flights to/from Europe and Asia.