Flight Soekarno–Hatta International Airport departs from Jakarta Soekarno–Hatta International Airport at 13:35 and arrives at Medan Kualanamu International Airport at 16:00.
The flighttime is about 2h 25m. The distance travelled ("as the bird flies"): 895 Km. So the average speed is roughly 370 Km.
The best month to arrive at Jakarta is January and the most expensive month to fly is March. (Average prices, based on 13069 datapoints.)
We have a lot more statistics for flights MH 118 and between Jakarta and Medan.