Flight Changi Airport departs from Singapore Changi Airport at 12:20 and arrives at Jakarta Soekarno–Hatta International Airport at 13:20.
The flighttime is about 2h 00m. The distance travelled ("as the bird flies"): 369 Km. So the average speed is roughly 184 Km.
There is an 1 hour time difference between Singapore and Jakarta
The best day to arrive at Singapore is Friday and it would be best to avoid Saturday, as prices are on average 112.3% higher than on Friday. (Average prices, based on 282187886 datapoints.)
We have a lot more statistics for flights EY 8134 and between Singapore and Jakarta.