Sydney Kingsford Smith International Airport, Australia. ScanSeats has route pages for 1 nonstop route from Sydney and 1 route into it, each with every airline on the route and how full its flights run in each month, from the records airlines file with the U.S. government for flights to and from the United States.
Compare every gateway between the United States and Sydney in the route explorer
Usually open means every airline on the route ran 80 percent full or less on average for that month in recent years. These are how full flights have run, not live seats or fares.