This is only quasi-New Zealand related, but this seemed to be the best place to post the question:

I and my wife want to go to New Zealand (from SF) next year sometime, and I'd really like us to be able to fly business class at least one way. I'm wondering what the most cost-effective way to do that (we're cost sensitive) is? Get an airline credit card (which? United?)? Something like a Chase Sapphire card?

Neither of us are frequent travelers, but we usually have a several thousand dollar credit card bill each month.

Suggestions appreciated...thanks!