This doesn't completely explain the flight number labelling issue in the article, but may be related: By convention, large airlines typically number their flig

This doesn't completely explain the flight number labelling issue in the article, but may be related: By convention, large airlines typically number their flights so that even-and-odd numbered pairs operate between the same two cities. For example, QF49 flies MEL-SFO and QF50 flies SFO-MEL.