Flight Juanda International Airport departs from Surabaya Juanda International Airport at 21:20 and arrives at Jakarta Soekarno–Hatta International Airport at 22:50.
The flighttime is about 1h 30m. The distance travelled ("as the bird flies"): 682 Km. So the average speed is roughly 455 Km.
The best day to arrive at Surabaya is Monday and it would be best to avoid Sunday, as prices are on average 35.92% higher than on Monday. (Average prices, based on 548090184 datapoints.)
We have a lot more statistics for flights QG 9721 and between Surabaya and Jakarta.