21.   Airlines tried using a profiling system to stop hijacking, he said, and that has not proved entirely successful.

22.   Airlines also try to provide frequent service from their hubs for the convenience of business travelers, who pay the highest fares.

23.   Airlines try to calculate all the angles.

24.   But analysts say that sooner or later, the airlines will try to raise fares again.

25.   But analysts say that sooner or later, probably sooner, the airlines will try to raise fares again.

26.   But as major airlines tried to compete against the new cut-rate carriers, they lost too much money and finally had to stop serving those routes.

27.   Caussade from Air France says the airline will try again soon.

28.   Commercial jets are so expensive that airlines try to keep them in the air, earning money, as much as possible.

29.   Despite the crush, one airline tried not only to return to the days of luxurious service but to make it as fun as possible.

30.   Fall is a traditionally light season for travel, and an unforeseen rise in capacity could damage profits as airlines tried to fend off upstarts.