Two years ago, the airlines were in panic mode. The country had just begun its unofficial lockdown and travel came to a halt. Revenue management models, the algorithms that told airlines how much they could charge for tickets, had become useless, since there was no price at which people would get on a plane. United Airlines had the most pessimistic outlook, estimating that sales would be down as much as 40%. Turns out that they were only wrong by about 60%....