The flight path took NZ26 over the Pacific north of Tahiti, above northern Mexico and over New Mexico, Kansas and Missouri before descending into in Illinois.
While the airline has flown a one-off charter flight to Chicago in 2014, but prior the start of regular three times a week services meant ''extensive'' homework for the group of pilots selected to fly the route, Hanley said.
''The air traffic control is something - listen how often they take a breath every minute - it's not very often. It's very busy.''
Read more: How Air NZ prepared for marathon Chicago flight
Pilots train on simulators to familiarise themselves with the airport, a domestic hub for American Airlines and Air New Zealand's commercial partner, United Airlines.
The first flight had 210 passengers and 14 crew on board. The aircraft is capable of carrying 275 passengers and the lighter load allowed it to take off 15 tonnes lighter than its maximum take off weight of 250 tonnes.
Air New Zealand's chief executive Christopher Luxon was on board and welcomed passengers with a PA announcement.
Before working for the airline, Luxon worked for Unilever and was based in Chicago for six years with his young family.
''I love Chicago - it's probably my second favourite place to live outside New Zealand..''
He said the architecture and art scene was outstanding.
''I think the best thing you can do is get yourself very quickly on to an architectural tour up the Chicago river - you get a real good feel of the history of the place.''
Luxon said the new route was strategically important to the airline putting it in the heart of a major population centre - Chicago with about 10 million people - and the US Midwest. The city is also less than two hours flying time from New York, an option for non-stop flights in the next few years.
More than 30 million Americans were considering New Zealand as a destination but just over 300,000 took the trip. Indirect flights, with inconvenient airport layovers were a deterrent.
The non-stop service would help push New Zealand up the bucket list, said Luxon.
Tourism minister Kelvin Davis said the Chicago flight would make it easier than ever for visitors from New Zealand's third-largest visitor market to get a taste of the country.
"We want a tourism industry that delivers productive, inclusive and sustainable growth. With nearly 60 per cent of American visitors travelling outside of the peak seasons, this new route will spread the benefits of tourism across the year and help to achieve our tourism goals."
In addition to tourism links, the United States is New Zealand's fourth-largest trading partner and one of the largest sources of direct investment.
"The more links we have with each other, the more opportunities there are for business, travel and people-to-people connections. This route will boost these opportunities and deepen the relationship between New Zealand and the United States," he said.
• The Herald travelled to Chicago courtesy of Air NZ