Speeds high
Quite right, a return on investment should not be seen in purely monetary terms. For a start, the government didn't have to pay out millions in state benefits to unemployed Air NZ workers. Keeping Air NZ alive was a good idea from several different angles.
stillalbatross
Seen from a standard Australian viewpoint (ie a little one-eyed). Niche players are often the most profitable- ask Mr Branson. Oh, and you might like to check your facts - the government didn't spend "a billion and a bit". The government invested NZD885 million in Air NZ, and have a 82% equity stake in the company. It is a public company, with shareholders.
Interesting that a "very sick company" has just posted a healthy profit.