Major airlines in the United States are reporting flight delays increasingly, but this has refused to dampen the spirit of the passengers and only fewer are complaining. This was disclosed in a recent study by the U.S. Department of Transportation.

According to the flight data provided by the federal Department of Transportation, only 68.9 percent of domestic airlines reported flights arrivals within 14 minutes of schedule in December 2013 as compared to 76.6 percent during the same month in 2012. The report said that flight cancellations also rapidly increased.

The report said that early December last year proved to be costly for the U.S. aviation industry. Thousands of flights were cancelled and delayed because of the freezing temperatures, ice and snow that inordinately put a stop on the operations of airlines at big hub airports in Dallas and Chicago.

Airlines were reported violating federal rules. The report citing these violations said that 10 flights were grounded during December 2013, and nine of these violations took place at Chicago’s O’Hare Airport on December 8, 2013.  

Prior to these cancellations and delays, the airlines were seen making sincere efforts to stay on schedule. According to the report, the on-time rate dropped to 78.3 percent for all or 2013, a decline of 3.6 percentage points as compared to 2012.

The report said that 16 airlines, including big carriers as well as leading regional carriers, were covered as revealed by the government figures. Small but growing carriers like Allegiant Air and Spirit Airlines are not included in the study.