Only three flights, operated by Delta, United and Pinnacle, were stuck on the tarmac for more than three hours that month - none because of the storm. International flights with lengthy delays weren't counted, including flights operated by Cathay Pacific and British Airways that spent over seven hours on the tarmac at New York's JFK airport.
U.S. airlines face fines of up to $27,000 per passengers for tarmac delays of more than three hours. From May, the first full month the rule was in effect, through December, 15 planes went past the three-hour mark, although no airline has been fined. There were 584 flights delayed on the tarmac for more than three hours in the same period a year earlier.
International airlines are not subject to the rule, even if they land or take off from U.S. airports. The Transportation Department is considering expanding the rule to include them.
More than 300 flights waited between two and three hours on the tarmac in December. Still, that's less than the 371 flights that experienced similar delays last December.
The December blizzard shut Northeast airports and led to nearly 10,000 cancellations by the 18 biggest U.S. airlines. There were almost 20,000 cancellations overall in December.
Cancellations aren't as costly as one might think. Canceling a flight eliminates fuel and labor costs. Many passengers will fly, just on later flights, so the airline still collects its fare.
By cancelling flights well ahead of bad weather, airlines are better able to keep planes moving through the rest of their networks. U.S. airlines operated 72 percent of their flights on time in December, the same as the year before. The on-time rate fell from November's 83.2 percent, however.
JetBlue, which canceled 1,400 flights in a span of five days before, during and after the blizzard, operated the fewest on-time flights last month. Only about 58.6 percent of its planes were on time. Three regional airlines that operate flights for major airlines - Comair, SkyWest and Pinnacle - also operated fewer than two-thirds of their flights on-time.
Southwest Airlines had an on-time rate of 67.1 percent. Southwest had one of the best records for getting passengers to their destinations on time because it favored secondary airports with less traffic. In 2009 the airline moved into busier airports like New York's LaGuardia and Boston's Logan, where it's trying to attract more business travelers.
Southwest also had the only flight - on its Baltimore-to-New York route - that was labeled "chronically delayed" for three straight months.
Hawaiian, United Airlines and AirTran had the highest on-time rates in December - all above 80 percent.
The DOT report said the number of complaints against airlines rose slightly in December compared to the same month of 2009. Passengers filed almost 600 complaints. Most of them were about canceled flights and mishandled baggage. Overall the airlines did a better job of handling bags, with fewer reports of lost or damaged luggage.
The government also said the airlines bumped fewer passengers from overbooked flights in the last quarter of 2009.