Airline mergers and high fuel prices are part of the reason. Jet fuel costs more than quadrupled from 2002 through 2012. Fuel costs now exceed labor costs as airlines' single largest expense, the GAO report said.
Major air carriers have also steered away from using the types of planes that serve smaller communities, regional airliners that seat from 19 to 100 passengers. Those planes are 40 percent to 60 percent less fuel-efficient on a per-passenger basis than larger planes used to service big airports, according to a Massachusetts Institute of Technology study the report cites.
Instead, major carriers are packing medium-size airliners with as many passengers as possible, operating planes that are on average 88 percent full, Gerald Dillingham, the accountability office's director of physical infrastructure issues, told a hearing of the House Transportation and Infrastructure Committee.
"While the largest airlines have shown a remarkable ability to adapt and earn profits the last four years, the reality is that many small communities are confronting increasing challenges in maintaining their desired level of air service," Susan Kurland, assistant secretary for aviation at the Department of Transportation, testified.
Regional airlines, which typically feed passengers from smaller airports to major carriers at larger airports, have proven less adaptable. Bryan Bedford, president and CEO of Republic Airways Holdings, a regional carrier that flew 21.5 million passengers last year, said economic pressures on regional airlines have been exacerbated by a shortage of entry-level airline pilots.
Republic identified 2,400 pilots who might be qualified for 500 pilot openings, but ultimately was able to hire only 450 because the rest didn't meet the company's standards, Bedford said. As a result, 27 regional airliners were grounded because the airline was 50 pilots short of its hiring goal.
But Air Line Pilots Association President Lee Moak told the committee there's no shortage of qualified airline pilots, only a shortage of pilots willing to work for the "near poverty" wages that regional airlines offer entry-level first officers.