Flight Brisbane Airport departs from Brisbane Brisbane Airport at 06:30 and arrives at Sydney Sydney Airport at 09:05.
The flighttime is about 2h 35m. The distance travelled ("as the bird flies"): 680 Km. So the average speed is roughly 263 Km.
The best day to arrive at Brisbane is Monday and it would be best to avoid Wednesday, as prices are on average 134.39% higher than on Monday. (Average prices, based on 5424279 datapoints.)
We have a lot more statistics for flights ZL 309 and between Brisbane and Sydney.