There's about the shortest viable route I can imagine. I could see refueling stops being a thing, though. SFO-SIN is a pretty long flight, so an hour to refuel in Tokyo wouldn't be so bad.
Right, this (Tokyo - Seattle) seems like a minimum viable Pacific crossing.
San Francisco to Tokyo is 5,133 miles, so it is out of range.
How about San Francisco to Hawaii, Hawaii to Tokyo, and Tokyo to Singapore. ;)
There's about the shortest viable route I can imagine. I could see refueling stops being a thing, though. SFO-SIN is a pretty long flight, so an hour to refuel in Tokyo wouldn't be so bad.