Originally Posted by LBJ

You are assuming that NW/DL Elites currently fly in roughly equal numbers on each others' airline. I would be shocked if the average DL flight has more than 1 or 2 NW Elites (and vice-versa for NW flights). Of course, reciprocal upgrades will encourage more crossing-over. However, when a new flyer crosses over, they will be freeing up an FC seat they would have normally occupied on their previous airline of choice. Thus making it available to a flyer crossing over in the opposite direction (who in turns frees up an FC seat when they cross-over).

So, there will be a slight dilution from the current status where the few crossovers do not grab the upgrades of the partner airline fliers, but there will certainly not be a "doubling" of competitors (due to your brethren fliers crossing in the opposite direction). In the end, you will have the combined pool elites drawing upgrades from the combined fleets of both airlines and not much difference from the current status quo.

To put it another way, let's say there are 10,000 combined NW/DL Elites flying on a given day with 10% (or 1,000) currently crossing over. Those 1,000 are currently not eligible for upgrades, so the upgradable pool would currently be 9,000 fliers on a given day. The reciprocal upgrades will simply put those 1,000 fliers back in the upgrade pool, increasing it to the full 10,000 flying Elites. So the dilution effect will be fairly minimal as the percentage increase from 9,000 to 10,000 fliers is not all that great.

I realize there are a couple of assumptions here -- that the current number of crossovers is small and that the new crossovers will be roughly equal in each direction. If anyone has hard facts on the number current crossovers, I'd like to hear about it.