Airlines today do not typically use refueling stops, rather they connect to other flights at major airports.
Between IAD and DXB airports United airlines has direct flights
A flight from Brisbane to Dubai is a 22 hour flight. This flight advertises as a non stop flight but will stop to refuel.
Emirates
For direct flights, about 17.5 hours flying time.
From DC to Dubai, 13 hours. From Dubai to DC, 15 hours.
The estimated flying time from London to Dubai is 10 hours and 55 minutes. The flight times will vary depending on the airline.
14 hours
About 6 hours.
Flying type :)
3.30hrs
About 4 hours flying time!
40 minutes
3