Originally Posted by
jrl767
running the sweep by flight number sequence would prioritize DL mainline over DL Connection; although this logic doesn't really seem equitable, in the interest of simplicity I can understand why it might have been implemented
an unintended consequence is that, since each DL Connection carrier has its own block of flight numbers, pax starting on Endeavor (2xxx and 3xxx) would be processed before pax starting on SkyWest (4xxx) and ShuttleAmerica (7xxx) ...
Who says that free elite upgrades at the window are processed passenger by passenger rather than flight by flight? IMO this would violate DL's published rules regarding upgrade priority as it would give the advantage to the person with the lowest flight number in their itinerary, even over other elites of the same tier with higher fare classes, PMs over DMs with higher flight numbers, etc.
I've never observed it happen to flights of mine, but surely someone who is watching for upgrades has seen a flight with a low number get upgraded and then a flight with a higher number some time later, all for travel on the same ticket for the same day.