Originally Posted by
SeenItAll
While this is likely correct, I have always wondered why there were so few late afternoon (or early evening) flights from Europe to the U.S.
Couple of reasons. Firstly such flights, by the time they turn round at destination, would be departing back to Europe undesirably late. Departures at 23.00 don't appeal to business travellers who have finished in the downtown office at 17.00. What on earth do you do ? Take an earlier flight with the competition, of course.
But most routes have some optimal times, based on connections at both ends. This is not just airline connections, but also surface ones. Arriving in the US notably late in the evening, and needing to allow for immigration/baggage collection delays, you may find your last onward travel has gone. It's a similar approach to that discussed for the daylight South Africa-Europe flights. If you arrive at Heathrow at 20.30 and want to go on to Dublin/Manchester/Edinburgh etc, let alone mainland Europe, your last flight will be unreliable or gone. Similar considerations for late arrivals in the USA, plus you will be jet-zonked feeling it's the middle of the night.
Even the much-vaunted O&D passengers will be trying to get home. I have got back to Heathrow at 21.30, and only just made the last Underground to my house, in London. Not everyone is getting a cab to a hotel. Even worse if you get to the hotel, or your house, at midnight, time zone-shifted, and tomorrow's meeting in the office starts at 08.00.