You can easily determine the time of flight between any two points on Earth
WeMakeMaps is an online flight time and distance calculator for billions of travel routes. Type in and chose from the list a city, or airport, or region, or country, or any other geographical point to figure out the flight time and distance between any two objects.
The service uses the great circle distance and the average airspeed of a commercial airliner (510 m/h or 820 km/h) to calculate how long would it take to fly from one city to another.