In this reality, Charles Xavier became the Juggernaut who formed the X-Men. Thunderbird is a member of Charles Xavier's X-Men who serves as a police force that aids the mutants and persecutes the sapiens.
The total flight duration from Sydney, Australia to Boston, MA is 20 hours, 41 minutes. This assumes an average flight speed for a commercial airliner of 500 mph, which is equivalent to 805 km/h or 434 knots. It also adds an extra 30 minutes for take-off and landing. Your exact time may vary depending on wind speeds.
Flight time from Brisbane to Bangkok is 9 hours 10 minutes. Non-stop flights could take upto 9 hours 15 minutes. Quickest one-stop flight takes close to 11 hours. However, some airlines could take as long as 35 hours based on the stopover destination and waiting duration.