About one in five U.S. flights arrived at least 15 minutes late in November, and passengers on four planes sat on the tarmac for more than three hours, a violation of federal rules.

The U.S. Department of Transportation said Tuesday that on the 14 airlines that carry the most passengers, 80.6 per cent of flights arrived on time in November. That was better than October’s 80.0 per cent on-time rate, but down from 83.5 per cent in November 2013.

AirTran topped the ratings, beating frequent leader Hawaiian Airlines. Regional carrier Envoy Air finished at the bottom.

Airlines cancelled 4,301 domestic flights, or just under 1 per cent, slightly lower than the rate a year earlier.