Depending on where you stop to refuel, about 28 hours.
A flight from Heathrow to Adelaide would take about 21 hours.
flight time from heathrow to Singapore
the flight time from Paris to heathrow is 50 min to one houre
The flight time from Adelaide, Australia to Darwin, Australia is approximately three and a half hours.
The flight time from Oslo, Norway to London Heathrow Airport is about 1 hour, 27 minutes.
The average flight time from London Heathrow Airport to Toulouse, France is 1 hour, 6 minutes.
About an hour.
The average flight time from London Heathrow Airport to Philadelphia International Airport is 7 hours, 5 minutes.
The flight time is 6 hours.
The flight time is 8 hours, 1 minute.
The flight is just over an hour long in actual time (remember that Melbourne is half an hour ahead of Adelaide's time.)
The average flight time from London Heathrow Airport to Lima, Peru is 12 hours, 36 minutes.