Through Topeka airport, the volume of plane travel is just enough for the commercial airlines to make modest profits. The size of the city's population is stable and is not expected to increase much. Yet there are investors ready to double the number of flights to and from the airport within ten years, and they are predicting solid profits both for themselves and for the established airlines.
Which of the following about the city of Topeka, if true, most helps to provide a justification for the investors' prediction?
【选项】
The average number of seats per flight is lower among existing routes than it is among routes still in the planning stages.
选项是否正确？