The airline industry has never generated sustained profits — by some estimates if you add up all the profits and losses since the Wright Brothers flew from Kitty Hawk in 1903, the net would be written in red ink. This year will be no different. The global industry will lose an estimated $9 billion, after running losses of $10.4 billion last year.

The question now is which carriers will survive the current downturn, offering what sort of schedules and service. Not an easy question, since two forces are at work: The current, temporary cyclical downturn, and a permanent change in travel habits.