Given that Delta is still flying the even older MD-88 and MD-90, who knows when Delta will retire the 717s? But certainly, at least some of the A220s will eventually pick up that flying as well. But the point still remains.

And both Airbus through the purchase of 51% of the A220 and Boeing through the purchase of pretty much the entire civilian side of Embraer have signaled their intention to get in the "jumbo RJ" contest. It is possible, I suppose, that the major pilots will give ground in scope, but I doubt it, short of a bankruptcy contract.

Yet the increased fuel efficiency of these aircraft mean they are going to be flown by SOMEBODY because they are going to be money makers. That may be someone like Moxy, flying them on long thin routes, or it may be the majors (or perhaps Horizon since Alaska has no scope) flying them on the longer less thin routes that many regionals fly 70 and 76 pax aircraft on today.

Clearly, some flying currently done by regionals, especially the flying between major airports, will tend to gravitate to the larger more efficient aircraft. Does that mean the smaller codeshares go away? Probably not, but I do anticipate they will increasingly be competing with newer, increasingly efficient 100+ seat narrow bodies, whoever is flying them.

We'll see.