I recently did UA 32, SFO-BOS redeye. We were scheduled in at 6:54am, but arrived 10 mins early at 6:44am. I deplaned, used the men's room, and then (still half-asleep) saw a gate for ORD. I thought it might be my return flight, so wandered over.

It was instead an earlier BOS-ORD that was fully boarded, so I just asked about standby and 3 mins later was on the plane with the cabin door closing.

Funny: the cabin door was closed on my return before my inbound flight was even scheduled to arrive! I was in Boston Logan airport for less than 8 mins.

When we deplaned in ORD, I found another ORD-SFO outbound that was already fully-boarded and I got on that one standby as well, to make it back to SFO by 11:25am.

So, 13 hrs SFO-BOS-SFO, 417mph avg (including stops) but obviously stopping in ORD hurt me.

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I'm betting other FTers have even quicker double transcons?!