A couple of points...
1) The agreement between US Airways, ATSB, and the banks, has the ATSB loan collateralized with slots and other assets. Now that the BK judge is allowing US Airways to dip into its ATSB loan money to operate (i.e. using unrestricted cash below the miniumums that ATSB agreement provides for), this means that now, US Airways does not have enough cash on hand to pay back the ATSB loan. This means, in my opinion, that it is increasingly likely for the ATSB to force liquidation. All ATSB has to do is call the loan, UAIRQ cannot pay for it, and must sell something.
2) The agreement between UAIRQ, ATSB, and the banks is a contract. Voiding contracts is a power of the BK court. It seems that every so-slighty, the BK judge is voiding the ATSB contract, by allowing UAIRQ to no longer adhere to the contracts covenants. By doing so, the ATSB could end up being free from its end of the deal (i.e. the guarantee), and the banks could demand their cash. Its all an interpretation of the law and the contract... This will be interesting to watch, from a legal perspective.
3) I don't believe BK was filed solely to deal with labor. The reality is that UAIRQ must still negotiate with labor, under court supervision. UAIRQ is not allowed to just void the contract and impose its own wage structure. Frank Lorenzo, who did just that at CAL many moons ago, forced the changes in BK law to prevent this from happening again. While UAIRQ is certainly targeting labor, it is in BK for one reason: not enough cash to pay the bills.
My best wishes to everyone still connected to US Airways.