Flight Soekarno–Hatta International Airport departs from Jakarta Soekarno–Hatta International Airport at 07:30 and arrives at Medan Kualanamu International Airport at 09:50.
The flighttime is about 2h 20m. The distance travelled ("as the bird flies"): 895 Km. So the average speed is roughly 384 Km.
The best month to arrive at Jakarta is October and the most expensive month to fly is February. (Average prices, based on 357 datapoints.)
We have a lot more statistics for flights OD 204 and between Jakarta and Medan.