The layover is something most people dispise they want to get from A to B as quick as possible. The concept of flying somewhere else to catch a flight is alien to them, unless the ticket they buy insists on it. Recently a friend asked advise on flights to Miami from Dublin. There were really cheap fares from Düsseldorf so I advised get yourself there and connect. In the end they paid over €300 extra each and connected in London anyway.
Sure there is some risk if your initial flight is cancelled and you miss the connection it’s on you but if you give yourself enough time you would be pretty unlucky for this to happen. But the real beauty of traveling like this is getting to see places you might not otherwise go to.
Taxes and fees are notoriously high flying to the US out of London, but low coming back in. So I tend to use miles to fly from the US to London but not the other way around as the out of pocket makes it pretty pointless. The problem up until recently was there weren’t many options when booking one way flights. Often one way is more expensive than a return on the major carriers.
On one trip I found a super cheap evening fare out of Copenhagen. Then booked an early morning date to get there. All in it cost about £130 and I got to spend a day sightseeing in Copenhagen which was really enjoyable and somewhere I likely never would have had a reason to visit.
Sure you spend some money on activities when you do this but you could be spending €600 extra to spend five hours in Heathrow…..