In 1971, the department was reorganized as a semi-independent agency of the federal government. Its name was changed to the United States Postal Service (USPS). New laws also removed the Postmaster General from the line of succession for the presidency.
The calculation of flight time is based on the straight line flight distance from Honolulu, HI to Atlanta, GA (as the crow flies), which is about 4,500 miles or 7 242 kilometers. Your trip begins in Honolulu, Hawaii. It ends in Atlanta, Georgia.
Why not stop over in Honolulu for a day or two each way? AA has direct flights from Chicago to HNL, and Hawaiian Airlines flies between HNL and SYD. In fact, Hawaiian currently has HNL to SYD on sale ($200 off) if you use Ecertificate # P09021 when you purchase the ticket.