Flight Sydney Airport departs from Sydney Sydney Airport at 21:35 and arrives at Brisbane Brisbane Airport at 23:05.
The flighttime is about 1h 30m. The distance travelled ("as the bird flies"): 680 Km. So the average speed is roughly 453 Km.
The best month to arrive at Sydney is April and the most expensive month to fly is October. (Average prices, based on 1114 datapoints.)
We have a lot more statistics for flights KE 556 and between Sydney and Brisbane.