The Boeing 777-300ER flew over the airport and did a few circuits. The runway at Wanaka is not long enough for it to take off or land. It is one of the more modern aircraft in the Air New Zealand fleet (which consists of both Boeing and Airbus jets as well as various smaller prop aircraft such as the ATR).
I thought the plane looked really good in its black and white colours. Maybe Air New Zealand should paint all their aircraft in this colour because it does look very sophisticated, it is distinctive, and the colours are associated with New Zealand (especially through the All Blacks).
The 777 has the most powerful engines of any airliner. A single engine has more power than all 4 used in the original 747 and that single engine would be enough to allow a current 747 to cruise safely. It is also very safe because since 1995 when the 777 was introduced 1361 have been delivered but there have been no fatalities although there were 8 "incidents".
Specs for 777-300ER:
Sources: Wikipedia, Warbirds Over Wanaka 2012 Programme.