Chip:
And while we're throwing around wild theories about what Mesa's potential purchase of ACA will or won't do for US Airways, please consider the following alternative scenario.
Let's assume Mesa completes the purchase of ACA. Ornstein then thinks to himself, "I've now got around 140 RJs in service or on order to feed United, but only a few dozen feeding US Airways. If I put all my effort with United, it will give me more leverage when the fee-per-departure rates are negotiated again." So he pulls his RJs from the US Airways operation.
At the same time, Mesa's move causes US Airways to come to the realization that, with or without Mesa, its two hubs in Pennsylvania can't handle the substantial future RJ growth that was implicit in the carrier's plan to return to profitability (and the very public dispute with the IAM regarding Airbus maintenance doesn't help either). PIT doesn't have the O&D to support it, and PHL doesn't have the runway expansion capability to support it. So while US Airways won't completely abandon those two cities, it does begin to shift flights to IAD to feed United's hub there, where the local O&D and runway expansion opportunities are much better. Eventually, this leads to a UCT/ICT, but it is the reborn United doing the buying (US Airways' IAD feed and the CLT hub), and US Airways subsequently disappears (at least from public view) as a separate entity.
Back to reality. Is the above likely to happen? Probably not, but IMHO it is no more implausible than your idea that Mesa will buy ACA and then take the combined company over to US Airways, totally ignoring Ornstein's public claims to the contrary. You'll have to do a lot more than again cite your "secret sources" or boldly claim (without any support) that "Time will tell, but unless something changes, I am dead on accurate" to convince me and most other readers of this thread that there is any substance to your theory.