One thing for the OP to remember: I'd imagine Air NZ's lenders (i.e. the banks and the government) have general security agreements over the most valuable assets of the company, i.e. planes and plant. Even if that's not true, financiers certainly will have individual securities over most of these individual pieces of these most valuable assets of Air NZ because Air NZ certainly would have borrowed to buy any plane that it owns. In the event of insolvency, secured creditors like the above rank ahead of everyone else and get first dips over secured assets, then preferential creditors (i.e. employees and the IRD) come into play, and the leftovers are for unsecured creditors (e.g. passengers who have prepaid for flights). At the best of times, you do not want to be an unsecured creditor. With businesses that basically rely on cashflow and don't hold much tangible assets, you aren't gonna see much -- if at all -- as an unsecured creditor.
GZ, despite the site owner's very best efforts, does not escape a common curse of internet forums: most posters are incredibly ignorant when it comes to matters of law and general principles/notions of commerciality. On the former, people just seem to think it's a free for all. From my observations, @Handle9 is one of the few on here that has a genuine and informed grasp of both (albeit necessarily that of a layperson's view from the legal perspective). He's right on the point of Air NZ needing to behave commercially: given the unusual circumstances (i.e. that it's not unreasonable for Air NZ to believe that its Ts&Cs might prevail - that doesn't necessarily mean it is right. Only the courts can confirm this) and the solvency threat that Air NZ is under, it's actually more than reasonable for Air NZ to behave as it has. If it turns out that it has to disgorge all the prepaid airfares for flights affected by COVID-19, people in your position might find it to be a Pyrrhic victory when placed in the position of an unsecured creditor in liquidation.
As with most things in life, the truth is complicated and often hard to bear.