Flight Kualanamu International Airport departs from Medan Kualanamu International Airport at 19:20 and arrives at Jakarta Soekarno–Hatta International Airport at 21:40.
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 Medan is January and the most expensive month to fly is April. (Average prices, based on 369 datapoints.)
We have a lot more statistics for flights SJ 11 and between Medan and Jakarta.