Contrary to popular belief, New Zealand didn't sell their entire air force to Australia. They still have an air force, they just sold their fighters to various people around the world. They have still have transport planes however, some helicopters and some snazzy trainers.

So should anyone ever invade New Zealand, New Zealand won't able to fight them from the sky, but they will be able to move things about with skill. But it's not all bad for New Zealand if they get invaded their navy has two combat ships which should keep any invading force busy for a while.

For those who are wondering, this is the entire New Zealand Air Force:

2 Boeing 757, 5 C-130H Hercules, 6 P3-K Orions, 14 Bell UH-1H Iroquois, 5 Bell 47G Sioux, 13 Aerospace CT-4E Airtrainer, and 5 Beech King Air B200. (From here)