Flight Achmad Yani International Airport departs from Semarang Achmad Yani International Airport at 16:35 and arrives at Jakarta Soekarno–Hatta International Airport at 17:50.
The flighttime is about 1h 15m. The distance travelled ("as the bird flies"): 415 Km. So the average speed is roughly 332 Km.
The best day to arrive at Semarang is Wednesday and it would be best to avoid Thursday, as prices are on average 21.02% higher than on Wednesday. (Average prices, based on 134651884 datapoints.)
We have a lot more statistics for flights GA 8751 and between Semarang and Jakarta.