We left Hong Kong at 2:30. One nice thing about Kowloon station- you can actually check in for your flight at the train station. They check your bags so when you take the high speed train back to the airport (2 stops from Kowloon) you don't have to worry about luggage and can just breeze through the gate. The flight from Hong Kong to Hanoi was not that long- 2 hours. We flew Vietnam Airlines.Vietnam Airlines is owned by the government.