Flight Soekarno–Hatta International Airport departs from Jakarta Soekarno–Hatta International Airport at 13:45 and arrives at Surabaya Juanda International Airport at 15:15.
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 month to arrive at Jakarta is January and the most expensive month to fly is April. (Average prices, based on 2425 datapoints.)
We have a lot more statistics for flights IU 344 and between Jakarta and Surabaya.