What conclusion are you drawing from this?
Average miles to 56 CONUS airports
My friend used to say that transportation business eventually comes down simple numbers as it gets more mature. The train freight business eventually breaks down to gradient of each companiy's tracks as that reflects the amount of energy needed to move the freight. Since prices even out, the company with the lower cost wins.
The airline business is not that cut and dried since so much revenue depends on premium seating which we have no insight.
But I would think that 923-996 average miles for ORD/ATL/DFW/CLT will keep the operations from airlines UA/AA/DL as the top in the country.
The further average distance from IAH and DEN will mean that they will not grow to the top of the heap despite their larger area for growth.
I must conclude that the international travel is still primarily about origin and destination so the JFK/LAX/MIA stay on top . We keep hearing about airlines moving inland like Qantas to DFW for the connections, but it hasn't shown up in the gross numbers.
STL is probably the airport closest to the center of CONUS, but I don't see it coming back to one of the largest airports again.