Well, without DOT data, it's hard to say what's likely to get cut, but that won't stop me from speculating irresponsibly.

Isn't the dark A319 limited to short haul intra-CA and SFO-LAS- they don't run it on *-SEA and *-JFK/IAD? And isn't it supposed to be gone into refit by the time Q4 rolls around in September, anyway? Some of the posts in the dark A319 thread seem to indicate that to be the case, and it would be the logical way to handle an expansion slowdown, especially since flying it kind of hurts the VX brand.

I would assume that some of the Q4 service they'll want to add is *-ORD, which wouldn't get a dark plane since those would be 3-4 hour flights, and the anecdotal reports I've heard is that midweek intra-CA/SFO-LAS is sort of light, which concurs with my limited observations (this summer, pricing out some of my future trips, I've found fairly cheap VX fares SEA-SFO-LAS midweek, but the prices are astronomical on weekends, and the LAS-SFO legs are packed on Sundays- in some cases, F is CHEAPER than Y).