A number of international airlines service New Zealand. Any travel agent will be pleased to assist you.
A plane.
yes
This would depend entirely on the country from which the commercial plane was flying.
Tampa, Florida is about 17 hours away from New Zealand when flying by plane. There is 8,122 miles between Florida and New Zealand.
Depends where you leave from......but it can take that long if you start off in Europe.
By plane or boat.
By boat and by plane
Distance from New Zealand to Croatia is: 11337.7 Miles (18246.3 Kilometers / 9845.7 Nautical Miles) Approximate travel time from Wellington, New Zealand to Zagreb, Croatia is 23 hrs, 33 mins
Private plane
By boat and by plane
45 minutes. It's only a 1hr 30m drive though so you are much better off driving.
Approx. 7 hours by plane.