Right now, August/2020 and September/2020 are the cheapest times in the year to fly to Chicago. The most expensive time of year is July/2020.
Qantas Airways and American Airlines have direct flights from Australia to Chicago.
The cheapest airline that flies from Australia to Chicago is Cathay Pacific.
The best airline to fly between Australia and Chicago is Qatar Airways. Qantas Airways is the best if you need direct flights. WestJet is the best low-cost airline.