I've gone on the assumption that routes departing or arriving between 2340 and 0600 see lower passenger demand.
Do I have this wrong?
Correct, but it is ok between 0500 to 0555.
Is this a hard and fast rule or are there exceptions? There are some domestic transcontinental flights that leave the US west coast at or after 2200 and arrive on the east coast between 0500-0700. Passengers may not seek out red eye flights but if the demand is there in AWS can an airline achieve good load factors on overnight flights?