Why is it just Qantas Sunfish?
I would expect that the low cost carriers will suffer the most and the quickest in a sustained debt crisis. Most LCC's are debt financed, highly leveraged with very low cash reserves. They rely on growth to sustain their business models.
It will be the major airlines with significant global alliances that that will be in the best position to negotiate the best deal within restrictive debt provisions.
There will also emerge a huge chinese/asian mega-carrier/alliance that will eat up many regional asian airlines. QF needs to be a part of it.