Butler said American was disappointed the airlines had been knocked back by the United States Department of Transportation for an expanded alliance on trans-Pacific routes and they would soon resubmit an application.
The airlines say the decision didn't take into account intense competition on trans-Pacific routes, or the benefits that a closer relationship between Qantas and American had already delivered.
American - which carries close to 200 million passengers a year - had just invested US$1.6 billion ($2.2b) in Los Angeles Airport, its Pacific hub.
"We think it's going to continue to grow and we have strong ambitions. I'm extremely bullish - it's only been a few years since we've got into the South Western Pacific."
The Boeing 787-9 that American will introduce has 285 seats in total, 59 seats more than the model it's replacing.
It will introduce premium economy seats to the route, a first for a US carrier.
Butler said the New Zealand market was familiar with premium economy and he predicted it would be popular.
Making routes such as the daily Auckland-Los Angeles service viable depended on both passengers and freight, he said.
The Boeing 787-8 had almost double the cargo capacity of an older generation 767-300 and that part of American's business had been performing strongly as it expanded its global reach. The next model 787 had even more capacity.
All cargo is in the belly of American's 1500 passenger planes rather than being in a dedicated freighter fleet.
American carries food from Auckland and Australia including lamb, beef, flowers, fish/seafood, honey, fruit, vegetables, spices, beverages, milk powder, as well as appliance parts.
From Los Angeles it ships pharmaceuticals, mail, general freight and fruit and vegetables.
Butler said cargo made up about 2 per cent or US$800 million of American Airlines' sales last year.
International Air Transport Association (IATA) figures show that air freight is buoyant.
Measured in freight tonne kilometres (FTKs), it rose 8.5 per cent in April compared to the year-earlier period.
IATA said while this was down from the 13.4 per cent year-on-year growth recorded in March, it is well above the average annual growth rate of 3.5 per cent over the past five years.