If half the financial sector is in the plane somehow, and they decide “oh, the airport has a power outage, better crash into the ocean instead,” that might make a major difference. More likely they will go land at a different airport or delay their travel, depending on there they are in the process.
You missed the parent's point, which is that a significant fraction of people flying to London because they have business to do in London, and the value of their time is not zero. If their time is wasted, that has a real cost in terms of lost productivity.
I don’t think I did miss their point. The loss is not the deletion of their productivity, it is the cost of shifting that productivity back by a day or so.
It’s just delays, not destruction.