Flight Changi Airport departs from Singapore Changi Airport at 15:40 and arrives at Penang Penang International Airport at 17:05.
The flighttime is about 1h 25m. The distance travelled ("as the bird flies"): 423 Km. So the average speed is roughly 299 Km.
The best day to arrive at Singapore is Monday and it would be best to avoid Sunday, as prices are on average 157.26% higher than on Monday. (Average prices, based on 2125670 datapoints.)
We have a lot more statistics for flights SQ 138 and between Singapore and Penang.