Originally Posted by
qasr
881 is a continuation flight, it is likely that the previous leg was late and possibly in nearby airspace.
881 originates in BOS as a 757, and had an on time departure. 881 continues from ORD (to NRT?) as a different aircraft, which would not have taken off until well after we'd landed. Or do you think there was some other United 881 some place on the east coast? This call sign was used throughout the flight.
I am impressed at how fast FTer's respond ^
On edit: OK, I get it, they wanted to distinguish even before the ORD-NRT aircraft departed. Thanks, gang!