From the Wall Street Journal
Big was bad when it came to airline service last year. Delta, American, United and its merger partner Continental placed last in the annual Middle Seat customer-service rankings of major domestic carriers in 2010.
Best among major airlines: smaller carriers. Alaska Airlines and AirTran Airways had the highest percentages of on-time flights and generally lower rates of lost bags, cancellations, passengers bumped from oversold flights and complaints filed with the Department of Transportation. Those two airlines were the only two majors to decrease their complaint totals in 2010—the rest shot higher.
Airline Scorecard: Which Carriers Were Best in 2010?
One source of the data was Flight Stats, which is a useful site for tracking flight status and airport delays on a regular basis.