21.   In the last few years, the largest carriers have begun installing self-service kiosks that resemble bank ATMs, primarily at hub airports.

22.   It had tried to make Greensboro, N.C., a small hub airport, but found demand lacking and shifted service to its more profitable, bigger hubs.

23.   Jackson said the airlines have created a monopolistic system with their hub airports, which he said represents a blatant violation of federal antitrust laws.

24.   Most airports whose malls have succeeded are hub airports, and hence are assured of a ready supply of shoppers trapped between flights.

25.   New management at the airline is trying to improve its service and focus its route network more on its hub airport in St. Louis.

26.   Now, those passengers can bypass the big hub airports.

27.   People who study airport retailing say the best-performing strips are in hub airports, where lots of passengers are changing planes and are thus forced to linger.

28.   Some of the major airlines have reorganized their schedules at their busiest hub airports to reduce peak congestion and added more spare planes.

29.   Such agreements have created important hub airports in Europe that together are beginning to threaten the long-dominant Heathrow.

30.   The airlines say that requiring bag-matching at busy hub airports would cause chaos.