Here’s the good news: The big airlines are revising their rules for booking and boarding flights — rules that led to one of the great business fiascos in recent history, United Express Flight 3411. Here’s the bad news: If the long-term lesson that leaders of the airline business (or any other business) take away from this episode is that it’s time to rewrite policies and practices, to fine-tune bureaucratic procedures, then they will have missed a huge, perhaps even historic, learning opportunity.