Airfares compared by airport and airline
Airport pair markets
The US Department of Transportation database provides information on selected airport pair markets in the US -- an airport pair market is defined by the combination of two connected airports. The latest download available contains data from the 4th quarter of 2014 on roughly 2,000 unique US airport pair markets.
Overall, the most recent data shows the following trend: The larger an airline carrier's market share is in a particular airport market, the higher per-mile airfare tends to get.