Flight Sydney Airport departs from Sydney Sydney Airport at 08:05 and arrives at Brisbane Brisbane Airport at 09:35.
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 day to arrive at Sydney is Monday and it would be best to avoid Friday, as prices are on average 96.18% higher than on Monday. (Average prices, based on 2637819 datapoints.)
We have a lot more statistics for flights QF 508 and between Sydney and Brisbane.