Re: No Warm Disaster Recovery Site?
I don't think this was a data center DR issue.
Instead, cancellations meant that aircrew and aircraft were in the wrong place, so each flight crew's schedule which goes from A->B->C->D->etc. ended up with a broken chain, breaking all the flights downstream.
The problem seems to have been the old scheduling software which apparently needed updates entered manually, one-by-one. And nothing in the software that allowed it to solve for: "Everything is scrambled. Find a set of flights to reset the system to start again cleanly the next morning".
It's not clear that point-to-point can't work with better scheduling software, especially since pilots often fly point-to-point multi-city routes for other airlines as well. But DR does not only cover data center failures -- an airline also needs "How to get from a state with everything messed up in the wrong place, back to a clean start-of-day state".