That would not be a correct presumption. Americans who travel to New Zealand are not at all representative of the general population. For one thing they are significantly more affluent on average. I suspect they're also older, and less likely to be suffering from severe chronic co-morbid conditions. For example, end-stage renal disease patients were heavily overrepresented among US COVID-19 deaths. Not many such people would get on a 16 hour flight to Auckland under any conditions.