Flight Brisbane Airport departs from Brisbane Brisbane Airport at 21:15 and arrives at Melbourne Melbourne Airport at 23:40.
The flighttime is about 2h 25m. The distance travelled ("as the bird flies"): 1343 Km. So the average speed is roughly 556 Km.
The best day to arrive at Brisbane is Monday and it would be best to avoid Friday, as prices are on average 161.19% higher than on Monday. (Average prices, based on 1177041 datapoints.)
We have a lot more statistics for flights QF 639 and between Brisbane and Melbourne.