Flight McCarran International Airport departs from Las Vegas McCarran International Airport at 16:50 and arrives at Los Angeles International Airport at 18:06.
The flighttime is about 1h 16m. The distance travelled ("as the bird flies"): 377 Km. So the average speed is roughly 298 Km.
The best day to arrive at Las Vegas is Friday and it would be best to avoid Sunday, as prices are on average 2412% higher than on Friday. (Average prices, based on 49950 datapoints.)
We have a lot more statistics for flights UA 684 and between Las Vegas and Los Angeles.