Continued from Part 1.

The fallout from a United Airlines (UAL:NYSE - news - boards)/US Airways (U:NYSE - news - boards) deal that never gets off the ground would affect many players in the industry and their stockholders, either directly or indirectly.

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The biggest casualty: US Airways' stockholders. With profits at the airline AWOL, and with management already thinking more about how to invest the postmerger haul than about running the airline, there's no doubt that the only thing propping up the stock price these days is the proposed deal.

Even then, the price still reflects a sizable insecurity about the merger, as there's still about a $20 spread between the price of the stock and the proposed $60 price tag. Are we taking any bets that the $60 price is still set in stone, and not negotiable, as US Airways' CEO Rakesh Gangwal said in the company's conference call in January?

It wasn't surprising, given the news on Thursday, that stock in US Airways brought up the rear for the majors, dropping back 5% to close at $37.38 on almost four times the normal volume. Friday it dropped another 8%, to close at $34.35.

On the other hand, it would be a mixed blessing for United shareholders if the deal were to fall through, in my opinion. On the one hand, I'm sure we'd hear a collective sigh of relief (not to mention a rise in the stock price) in terms of the massive reduction in earnings pressure that a collapsed deal would signal.

Oddly enough, despite the bad news on the wires, United stock was up 4% Thursday, to $40.65, then down only a hair to $39.89 at Friday's close. Is this wishful thinking?

Still, if the deal were to fall apart, investors' next big question would be: "Now what?" I think there's no doubt that, long term, United would have lost control of the war to substantially expand its network.

But in the shorter term there's no doubt a failed deal would see United stock rise. And CEO Jim Goodwin depart.

Which brings us to American Airlines' (AMR:NYSE - news - boards) stockholders. Remember that the American deal with TWA (which we feel will go through eventually) is not contingent upon the US Airways' deal going through with United. Smart cookies, those guys in Fort Worth.

So, while American has negotiated a nice deal with United for itself and its shareholders, if the merger between United and US Airways falls apart, American will still be sitting pretty. In more ways than one. American could pick up the remains of US Airways for cheap, or it could leave them on the table. Or it could pick over what is left with United. Either way, American gains.

And American will still have the assets from the TWA deal.

Atlantic Coast (ACAI:Nasdaq - news - boards) shareholders will also have a mixed bag of emotions to sort through if the deal fails. The current conditions of the merger call for Atlantic Coast to buy three of US Airways' commuter airlines. Atlantic Coast would pick up a ton of growth in terms of additional regional jet flying.

But, if the deal fails, Atlantic Coast will be OK. Actually, I'd like the stock more without the baggage of the three US Airways commuter operations. I have doubts about the ability of the Atlantic Coast management team to handle the expansion.

Mesa Airlines (MESA:Nasdaq - news - boards) has a lot at stake, having buried the hatchet with United on past legal tiffs. You will recall that United quit using Mesa three years ago as a United Express regional carrier because of Mesa's then-abysmal operational performance. The two sides have been rather cool toward each other ever since.

Now, however, Mesa is not the airline it was then, and United needs additional regional airline lift. Mesa has the birds on order.

This past week, the two airlines announced they had smoked the peace pipe, new routes are probably on the horizon for Mesa and an existing contract between US Airways and Mesa had been extended, per the merger's being approved.

If the United deal falls apart, this would dim Mesa's rosy horizon -- but it would by no means be a death knell.

More of a threat to Mesa is that it would still be contracted to fly for US Airways -- post merger collapse. This might not be such a great position to be in, as this flying is revenue-shared, not fly for hire.

In the end, the biggest loser if the deal falls through will be US Airways. And the biggest potential winner if the merger runs off the road will be American Airlines.

The airline that stands to gain the most, sitting from its comfy window seat next to the main show? Continental Airlines (CAL:NYSE - news - boards). Trust me. Continental does not want to be forced to merge with Delta Air Lines (DAL:NYSE - news - boards). They really don't want anything to do with Delta Air Lines.

If the United/US Airways deal falls apart, they won't have to worry about it. At least not for a while.