Flight Kansai International Airport departs from Osaka Kansai International Airport at 10:30 and arrives at Hanoi Noi Bai International Airport at 13:55.
The flighttime is about 5h 25m. The distance travelled ("as the bird flies"): 3339 Km. So the average speed is roughly 616 Km.
There is an 2 hour time difference between Osaka and Hanoi