These tables created by the Bureau of Transportation Statistics (BTS) summarize and provide historical comparisons of monthly on-time reports filed by large airlines. Flights are on-time if they depart from the gate or arrive at the gate less than 15 minutes after their scheduled departure or arrival times. For annual rankings, click on December, then select the year-to-date rankings.
Additional on-time information can be found in the Air Travel Consumer Report, http://www.transportation.gov/individuals/air-consumer/air-travel-consumer-reports.