Originally Posted by
pluto101
.... While United isn't a great option for the flight to Fiji, we can fly Air New Zealand to Auckland, then fly United back on its new 787 flight (seems more comfortable than ANZ's 777).
Tickets are expensive, obviously. But United's mileage upgrades seem like a good deal. ....
While you might be able to upgrade the UA flights with miles (if the upgrade inventory is available), that will not work for the NZ flights (only their most expensive economy fares can be upgraded and upgrade space is rare on NZ).