In good weather, there are few if any seriously delayed flights at the airport. If any two of the airport's runways are used simultaneously, serious delays result. In poor weather, only half as many planes are allowed to land each hour on any one runway at the airport as are allowed to land on it in good weather. Airlines using the airport base their schedules on the assumption that more than 30 planes an hour will be allowed to land at the airport.
The airport' s runways are too close to each other to allow simultaneous use of adjacent runways when visibility is poor, so the airport allows only 30 planes an hour to land in poor weather; in good weather 60 planes an hour are allowed to land. Because airline schedules assume good weather, bad weather creates serious delays.
Which one of the following is most strongly supported by the information above?