This was discussed this week on the frequent flyer forums.
They were saying that since Chapter 11 bankruptcy protection, their merger with America West has made them strong.

Here is the posting -

Several months ago, when US Airways' chief Doug Parker signaled that his airline shouldn't be overlooked in any discussions of candidates for future mergers, he wasn't taken very seriously. At the time, US Air was newly emerged from Chapter 11 and scrambling to make the merger with America West work. The new company hardly seemed positioned to undertake yet another tie-up.

Today he proved just how serious he was, going public with a surprise $8 billion hostile takeover bid for Delta Air Lines.

Five years ago, the idea would have been laughable -- two stodgy, high-cost airlines combining to create a bigger, stodgier, higher-cost uber-airline.

But today, US Air is really more America West than it is its namesake. With its low costs and energetic marketing, the new US Air looks to be a success in the making, eminently capable of acquiring and incorporating another carrier almost twice its size.

We'll have more information on what the merger would mean for members of US Air's Dividend Miles and Delta's SkyMiles programs in the coming weeks. For now, it's enough to say that no one needs to fret that miles will be lost or significantly devalued.

Here's one of the intriguing questions: assuming the merger goes forward, would the newly created carrier (which would retain the Delta name, according to Parker's proposal) elect to partner with the Star Alliance, as US Air does, or SkyTeam, currently co-anchored by Delta?

And then there's the question of the Atlanta and Charlotte hubs. Would both be maintained in the event of a merger? Just one? And in the latter case, which one?